diff --git a/.github/workflows/trigger-e2e-tests.yml b/.github/workflows/trigger-e2e-tests.yml
index ae34cbffe0..7111ee37fa 100644
--- a/.github/workflows/trigger-e2e-tests.yml
+++ b/.github/workflows/trigger-e2e-tests.yml
@@ -62,14 +62,14 @@ jobs:
 
   trigger-e2e-tests:
     needs: [ tag ]
-    runs-on: [ self-hosted, gen3, small ]
+    runs-on: ubuntu-latest
     env:
       TAG: ${{ needs.tag.outputs.build-tag }}
-    container:
-      image: 369495373322.dkr.ecr.eu-central-1.amazonaws.com/base:pinned
-      options: --init
     steps:
       - name: check if ecr image are present
+        env:
+          AWS_ACCESS_KEY_ID: ${{ secrets.AWS_ACCESS_KEY_DEV }}
+          AWS_SECRET_ACCESS_KEY: ${{ secrets.AWS_SECRET_KEY_DEV }}
         run: |
           for REPO in neon compute-tools compute-node-v14 vm-compute-node-v14 compute-node-v15 vm-compute-node-v15 compute-node-v16 vm-compute-node-v16; do
             OUTPUT=$(aws ecr describe-images --repository-name ${REPO} --region eu-central-1 --query "imageDetails[?imageTags[?contains(@, '${TAG}')]]" --output text)
@@ -79,41 +79,55 @@ jobs:
             fi
           done
 
-      - name: Set PR's status to pending and request a remote CI test
+      - name: Set e2e-platforms
+        id: e2e-platforms
+        env:
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         run: |
-          # For pull requests, GH Actions set "github.sha" variable to point at a fake merge commit
-          # but we need to use a real sha of a latest commit in the PR's branch for the e2e job,
-          # to place a job run status update later.
-          COMMIT_SHA=${{ github.event.pull_request.head.sha }}
-          # For non-PR kinds of runs, the above will produce an empty variable, pick the original sha value for those
-          COMMIT_SHA=${COMMIT_SHA:-${{ github.sha }}}
+          # Default set of platforms to run e2e tests on
+          platforms='["docker", "k8s"]'
 
-          REMOTE_REPO="${{ github.repository_owner }}/cloud"
+          # If the PR changes vendor/, pgxn/ or libs/vm_monitor/ directories, or Dockerfile.compute-node, add k8s-neonvm to the list of platforms.
+          # If the workflow run is not a pull request, add k8s-neonvm to the list.
+          if [ "$GITHUB_EVENT_NAME" == "pull_request" ]; then
+            for f in $(gh api "/repos/${GITHUB_REPOSITORY}/pulls/${PR_NUMBER}/files" --paginate --jq '.[].filename'); do
+              case "$f" in
+                vendor/*|pgxn/*|libs/vm_monitor/*|Dockerfile.compute-node)
+                  platforms=$(echo "${platforms}" | jq --compact-output '. += ["k8s-neonvm"] | unique')
+                  ;;
+                *)
+                  # no-op
+                  ;;
+              esac
+            done
+          else
+            platforms=$(echo "${platforms}" | jq --compact-output '. += ["k8s-neonvm"] | unique')
+          fi
 
-          curl -f -X POST \
-          https://api.github.com/repos/${{ github.repository }}/statuses/$COMMIT_SHA \
-          -H "Accept: application/vnd.github.v3+json" \
-          --user "${{ secrets.CI_ACCESS_TOKEN }}" \
-          --data \
-            "{
-              \"state\": \"pending\",
-              \"context\": \"neon-cloud-e2e\",
-              \"description\": \"[$REMOTE_REPO] Remote CI job is about to start\"
-            }"
+          echo "e2e-platforms=${platforms}" | tee -a $GITHUB_OUTPUT
 
-          curl -f -X POST \
-          https://api.github.com/repos/$REMOTE_REPO/actions/workflows/testing.yml/dispatches \
-          -H "Accept: application/vnd.github.v3+json" \
-          --user "${{ secrets.CI_ACCESS_TOKEN }}" \
-          --data \
-            "{
-              \"ref\": \"main\",
-              \"inputs\": {
-                \"ci_job_name\": \"neon-cloud-e2e\",
-                \"commit_hash\": \"$COMMIT_SHA\",
-                \"remote_repo\": \"${{ github.repository }}\",
-                \"storage_image_tag\": \"${TAG}\",
-                \"compute_image_tag\": \"${TAG}\",
-                \"concurrency_group\": \"${{ env.E2E_CONCURRENCY_GROUP }}\"
-              }
-            }"
+      - name: Set PR's status to pending and request a remote CI test
+        env:
+          E2E_PLATFORMS: ${{ steps.e2e-platforms.outputs.e2e-platforms }}
+          COMMIT_SHA: ${{ github.event.pull_request.head.sha || github.sha }}
+          GH_TOKEN: ${{ secrets.CI_ACCESS_TOKEN }}
+        run: |
+          REMOTE_REPO="${GITHUB_REPOSITORY_OWNER}/cloud"
+
+          gh api "/repos/${GITHUB_REPOSITORY}/statuses/${COMMIT_SHA}" \
+            --method POST \
+            --raw-field "state=pending" \
+            --raw-field "description=[$REMOTE_REPO] Remote CI job is about to start" \
+            --raw-field "context=neon-cloud-e2e"
+
+          gh workflow --repo ${REMOTE_REPO} \
+            run testing.yml \
+              --ref "main" \
+              --raw-field "ci_job_name=neon-cloud-e2e" \
+              --raw-field "commit_hash=$COMMIT_SHA" \
+              --raw-field "remote_repo=${GITHUB_REPOSITORY}" \
+              --raw-field "storage_image_tag=${TAG}" \
+              --raw-field "compute_image_tag=${TAG}" \
+              --raw-field "concurrency_group=${E2E_CONCURRENCY_GROUP}" \
+              --raw-field "e2e-platforms=${E2E_PLATFORMS}"
diff --git a/Cargo.lock b/Cargo.lock
index 45b802c54f..c1c245fa9c 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3581,6 +3581,7 @@ dependencies = [
  "strum_macros",
  "svg_fmt",
  "sync_wrapper",
+ "sysinfo",
  "tenant_size_model",
  "thiserror",
  "tokio",
diff --git a/compute_tools/src/spec.rs b/compute_tools/src/spec.rs
index 3b596a88ff..4006062fc2 100644
--- a/compute_tools/src/spec.rs
+++ b/compute_tools/src/spec.rs
@@ -302,9 +302,9 @@ pub fn handle_roles(spec: &ComputeSpec, client: &mut Client) -> Result<()> {
             RoleAction::Create => {
                 // This branch only runs when roles are created through the console, so it is
                 // safe to add more permissions here. BYPASSRLS and REPLICATION are inherited
-                // from neon_superuser. (NOTE: REPLICATION has been removed from here for now).
+                // from neon_superuser.
                 let mut query: String = format!(
-                    "CREATE ROLE {} INHERIT CREATEROLE CREATEDB BYPASSRLS IN ROLE neon_superuser",
+                    "CREATE ROLE {} INHERIT CREATEROLE CREATEDB BYPASSRLS REPLICATION IN ROLE neon_superuser",
                     name.pg_quote()
                 );
                 info!("running role create query: '{}'", &query);
@@ -806,19 +806,8 @@ $$;"#,
         "",
         "",
         "",
+        "",
         // Add new migrations below.
-        r#"
-DO $$
-DECLARE
-    role_name TEXT;
-BEGIN
-    FOR role_name IN SELECT rolname FROM pg_roles WHERE rolreplication IS TRUE
-    LOOP
-        RAISE NOTICE 'EXECUTING ALTER ROLE % NOREPLICATION', quote_ident(role_name);
-        EXECUTE 'ALTER ROLE ' || quote_ident(role_name) || ' NOREPLICATION';
-    END LOOP;
-END
-$$;"#,
     ];
 
     let mut query = "CREATE SCHEMA IF NOT EXISTS neon_migration";
diff --git a/control_plane/attachment_service/src/service.rs b/control_plane/attachment_service/src/service.rs
index aa930014b2..925910253b 100644
--- a/control_plane/attachment_service/src/service.rs
+++ b/control_plane/attachment_service/src/service.rs
@@ -1523,6 +1523,8 @@ impl Service {
         &self,
         create_req: TenantCreateRequest,
     ) -> Result<TenantCreateResponse, ApiError> {
+        let tenant_id = create_req.new_tenant_id.tenant_id;
+
         // Exclude any concurrent attempts to create/access the same tenant ID
         let _tenant_lock = self
             .tenant_op_locks
@@ -1531,7 +1533,12 @@ impl Service {
 
         let (response, waiters) = self.do_tenant_create(create_req).await?;
 
-        self.await_waiters(waiters, SHORT_RECONCILE_TIMEOUT).await?;
+        if let Err(e) = self.await_waiters(waiters, SHORT_RECONCILE_TIMEOUT).await {
+            // Avoid deadlock: reconcile may fail while notifying compute, if the cloud control plane refuses to
+            // accept compute notifications while it is in the process of creating.  Reconciliation will
+            // be retried in the background.
+            tracing::warn!(%tenant_id, "Reconcile not done yet while creating tenant ({e})");
+        }
         Ok(response)
     }
 
@@ -1610,13 +1617,25 @@ impl Service {
                 splitting: SplitState::default(),
             })
             .collect();
-        self.persistence
+
+        match self
+            .persistence
             .insert_tenant_shards(persist_tenant_shards)
             .await
-            .map_err(|e| {
-                // TODO: distinguish primary key constraint (idempotent, OK), from other errors
-                ApiError::InternalServerError(anyhow::anyhow!(e))
-            })?;
+        {
+            Ok(_) => {}
+            Err(DatabaseError::Query(diesel::result::Error::DatabaseError(
+                DatabaseErrorKind::UniqueViolation,
+                _,
+            ))) => {
+                // Unique key violation: this is probably a retry.  Because the shard count is part of the unique key,
+                // if we see a unique key violation it means that the creation request's shard count matches the previous
+                // creation's shard count.
+                tracing::info!("Tenant shards already present in database, proceeding with idempotent creation...");
+            }
+            // Any other database error is unexpected and a bug.
+            Err(e) => return Err(ApiError::InternalServerError(anyhow::anyhow!(e))),
+        };
 
         let (waiters, response_shards) = {
             let mut locked = self.inner.write().unwrap();
diff --git a/libs/metrics/src/hll.rs b/libs/metrics/src/hll.rs
index 46a623b0e2..dfb4461ce9 100644
--- a/libs/metrics/src/hll.rs
+++ b/libs/metrics/src/hll.rs
@@ -40,7 +40,7 @@ macro_rules! register_hll {
     }};
 
     ($N:literal, $NAME:expr, $HELP:expr $(,)?) => {{
-        $crate::register_hll!($N, $crate::opts!($NAME, $HELP), $LABELS_NAMES)
+        $crate::register_hll!($N, $crate::opts!($NAME, $HELP))
     }};
 }
 
diff --git a/pageserver/Cargo.toml b/pageserver/Cargo.toml
index f304294591..7a11610a91 100644
--- a/pageserver/Cargo.toml
+++ b/pageserver/Cargo.toml
@@ -59,6 +59,7 @@ signal-hook.workspace = true
 smallvec = { workspace = true, features = ["write"] }
 svg_fmt.workspace = true
 sync_wrapper.workspace = true
+sysinfo.workspace = true
 tokio-tar.workspace = true
 thiserror.workspace = true
 tokio = { workspace = true, features = ["process", "sync", "fs", "rt", "io-util", "time"] }
diff --git a/pageserver/src/bin/pageserver.rs b/pageserver/src/bin/pageserver.rs
index ef616c0a39..c80230d4d7 100644
--- a/pageserver/src/bin/pageserver.rs
+++ b/pageserver/src/bin/pageserver.rs
@@ -600,33 +600,37 @@ fn start_pageserver(
             None,
             "consumption metrics collection",
             true,
-            async move {
-                // first wait until background jobs are cleared to launch.
-                //
-                // this is because we only process active tenants and timelines, and the
-                // Timeline::get_current_logical_size will spawn the logical size calculation,
-                // which will not be rate-limited.
-                let cancel = task_mgr::shutdown_token();
+            {
+                let tenant_manager = tenant_manager.clone();
+                async move {
+                    // first wait until background jobs are cleared to launch.
+                    //
+                    // this is because we only process active tenants and timelines, and the
+                    // Timeline::get_current_logical_size will spawn the logical size calculation,
+                    // which will not be rate-limited.
+                    let cancel = task_mgr::shutdown_token();
 
-                tokio::select! {
-                    _ = cancel.cancelled() => { return Ok(()); },
-                    _ = background_jobs_barrier.wait() => {}
-                };
+                    tokio::select! {
+                        _ = cancel.cancelled() => { return Ok(()); },
+                        _ = background_jobs_barrier.wait() => {}
+                    };
 
-                pageserver::consumption_metrics::collect_metrics(
-                    metric_collection_endpoint,
-                    &conf.metric_collection_bucket,
-                    conf.metric_collection_interval,
-                    conf.cached_metric_collection_interval,
-                    conf.synthetic_size_calculation_interval,
-                    conf.id,
-                    local_disk_storage,
-                    cancel,
-                    metrics_ctx,
-                )
-                .instrument(info_span!("metrics_collection"))
-                .await?;
-                Ok(())
+                    pageserver::consumption_metrics::collect_metrics(
+                        tenant_manager,
+                        metric_collection_endpoint,
+                        &conf.metric_collection_bucket,
+                        conf.metric_collection_interval,
+                        conf.cached_metric_collection_interval,
+                        conf.synthetic_size_calculation_interval,
+                        conf.id,
+                        local_disk_storage,
+                        cancel,
+                        metrics_ctx,
+                    )
+                    .instrument(info_span!("metrics_collection"))
+                    .await?;
+                    Ok(())
+                }
             },
         );
     }
diff --git a/pageserver/src/config.rs b/pageserver/src/config.rs
index a29719e36f..1837da34ce 100644
--- a/pageserver/src/config.rs
+++ b/pageserver/src/config.rs
@@ -95,6 +95,8 @@ pub mod defaults {
 
     pub const DEFAULT_VALIDATE_VECTORED_GET: bool = true;
 
+    pub const DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB: usize = 0;
+
     ///
     /// Default built-in configuration file.
     ///
@@ -156,6 +158,8 @@ pub mod defaults {
 #heatmap_upload_concurrency = {DEFAULT_HEATMAP_UPLOAD_CONCURRENCY}
 #secondary_download_concurrency = {DEFAULT_SECONDARY_DOWNLOAD_CONCURRENCY}
 
+#ephemeral_bytes_per_memory_kb = {DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB}
+
 [remote_storage]
 
 "#
@@ -279,6 +283,13 @@ pub struct PageServerConf {
     pub max_vectored_read_bytes: MaxVectoredReadBytes,
 
     pub validate_vectored_get: bool,
+
+    /// How many bytes of ephemeral layer content will we allow per kilobyte of RAM.  When this
+    /// is exceeded, we start proactively closing ephemeral layers to limit the total amount
+    /// of ephemeral data.
+    ///
+    /// Setting this to zero disables limits on total ephemeral layer size.
+    pub ephemeral_bytes_per_memory_kb: usize,
 }
 
 /// We do not want to store this in a PageServerConf because the latter may be logged
@@ -400,6 +411,8 @@ struct PageServerConfigBuilder {
     max_vectored_read_bytes: BuilderValue<MaxVectoredReadBytes>,
 
     validate_vectored_get: BuilderValue<bool>,
+
+    ephemeral_bytes_per_memory_kb: BuilderValue<usize>,
 }
 
 impl PageServerConfigBuilder {
@@ -486,6 +499,7 @@ impl PageServerConfigBuilder {
                 NonZeroUsize::new(DEFAULT_MAX_VECTORED_READ_BYTES).unwrap(),
             )),
             validate_vectored_get: Set(DEFAULT_VALIDATE_VECTORED_GET),
+            ephemeral_bytes_per_memory_kb: Set(DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB),
         }
     }
 }
@@ -665,6 +679,10 @@ impl PageServerConfigBuilder {
         self.validate_vectored_get = BuilderValue::Set(value);
     }
 
+    pub fn get_ephemeral_bytes_per_memory_kb(&mut self, value: usize) {
+        self.ephemeral_bytes_per_memory_kb = BuilderValue::Set(value);
+    }
+
     pub fn build(self) -> anyhow::Result<PageServerConf> {
         let default = Self::default_values();
 
@@ -720,6 +738,7 @@ impl PageServerConfigBuilder {
                 get_vectored_impl,
                 max_vectored_read_bytes,
                 validate_vectored_get,
+                ephemeral_bytes_per_memory_kb,
             }
             CUSTOM LOGIC
             {
@@ -1010,6 +1029,9 @@ impl PageServerConf {
                 "validate_vectored_get" => {
                     builder.get_validate_vectored_get(parse_toml_bool("validate_vectored_get", item)?)
                 }
+                "ephemeral_bytes_per_memory_kb" => {
+                    builder.get_ephemeral_bytes_per_memory_kb(parse_toml_u64("ephemeral_bytes_per_memory_kb", item)? as usize)
+                }
                 _ => bail!("unrecognized pageserver option '{key}'"),
             }
         }
@@ -1091,6 +1113,7 @@ impl PageServerConf {
                     .expect("Invalid default constant"),
             ),
             validate_vectored_get: defaults::DEFAULT_VALIDATE_VECTORED_GET,
+            ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB,
         }
     }
 }
@@ -1328,6 +1351,7 @@ background_task_maximum_delay = '334 s'
                         .expect("Invalid default constant")
                 ),
                 validate_vectored_get: defaults::DEFAULT_VALIDATE_VECTORED_GET,
+                ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB
             },
             "Correct defaults should be used when no config values are provided"
         );
@@ -1399,6 +1423,7 @@ background_task_maximum_delay = '334 s'
                         .expect("Invalid default constant")
                 ),
                 validate_vectored_get: defaults::DEFAULT_VALIDATE_VECTORED_GET,
+                ephemeral_bytes_per_memory_kb: defaults::DEFAULT_EPHEMERAL_BYTES_PER_MEMORY_KB
             },
             "Should be able to parse all basic config values correctly"
         );
diff --git a/pageserver/src/consumption_metrics.rs b/pageserver/src/consumption_metrics.rs
index 3429e3a0a6..f5540e896f 100644
--- a/pageserver/src/consumption_metrics.rs
+++ b/pageserver/src/consumption_metrics.rs
@@ -3,7 +3,9 @@
 use crate::context::{DownloadBehavior, RequestContext};
 use crate::task_mgr::{self, TaskKind, BACKGROUND_RUNTIME};
 use crate::tenant::tasks::BackgroundLoopKind;
-use crate::tenant::{mgr, LogicalSizeCalculationCause, PageReconstructError, Tenant};
+use crate::tenant::{
+    mgr::TenantManager, LogicalSizeCalculationCause, PageReconstructError, Tenant,
+};
 use camino::Utf8PathBuf;
 use consumption_metrics::EventType;
 use pageserver_api::models::TenantState;
@@ -41,6 +43,7 @@ type Cache = HashMap<MetricsKey, (EventType, u64)>;
 /// Main thread that serves metrics collection
 #[allow(clippy::too_many_arguments)]
 pub async fn collect_metrics(
+    tenant_manager: Arc<TenantManager>,
     metric_collection_endpoint: &Url,
     metric_collection_bucket: &Option<RemoteStorageConfig>,
     metric_collection_interval: Duration,
@@ -67,15 +70,19 @@ pub async fn collect_metrics(
         None,
         "synthetic size calculation",
         false,
-        async move {
-            calculate_synthetic_size_worker(
-                synthetic_size_calculation_interval,
-                &cancel,
-                &worker_ctx,
-            )
-            .instrument(info_span!("synthetic_size_worker"))
-            .await?;
-            Ok(())
+        {
+            let tenant_manager = tenant_manager.clone();
+            async move {
+                calculate_synthetic_size_worker(
+                    tenant_manager,
+                    synthetic_size_calculation_interval,
+                    &cancel,
+                    &worker_ctx,
+                )
+                .instrument(info_span!("synthetic_size_worker"))
+                .await?;
+                Ok(())
+            }
         },
     );
 
@@ -116,7 +123,7 @@ pub async fn collect_metrics(
         let started_at = Instant::now();
 
         // these are point in time, with variable "now"
-        let metrics = metrics::collect_all_metrics(&cached_metrics, &ctx).await;
+        let metrics = metrics::collect_all_metrics(&tenant_manager, &cached_metrics, &ctx).await;
 
         let metrics = Arc::new(metrics);
 
@@ -271,6 +278,7 @@ async fn reschedule(
 
 /// Caclculate synthetic size for each active tenant
 async fn calculate_synthetic_size_worker(
+    tenant_manager: Arc<TenantManager>,
     synthetic_size_calculation_interval: Duration,
     cancel: &CancellationToken,
     ctx: &RequestContext,
@@ -283,7 +291,7 @@ async fn calculate_synthetic_size_worker(
     loop {
         let started_at = Instant::now();
 
-        let tenants = match mgr::list_tenants().await {
+        let tenants = match tenant_manager.list_tenants() {
             Ok(tenants) => tenants,
             Err(e) => {
                 warn!("cannot get tenant list: {e:#}");
@@ -302,10 +310,14 @@ async fn calculate_synthetic_size_worker(
                 continue;
             }
 
-            let Ok(tenant) = mgr::get_tenant(tenant_shard_id, true) else {
+            let Ok(tenant) = tenant_manager.get_attached_tenant_shard(tenant_shard_id) else {
                 continue;
             };
 
+            if !tenant.is_active() {
+                continue;
+            }
+
             // there is never any reason to exit calculate_synthetic_size_worker following any
             // return value -- we don't need to care about shutdown because no tenant is found when
             // pageserver is shut down.
@@ -343,9 +355,7 @@ async fn calculate_and_log(tenant: &Tenant, cancel: &CancellationToken, ctx: &Re
     };
 
     // this error can be returned if timeline is shutting down, but it does not
-    // mean the synthetic size worker should terminate. we do not need any checks
-    // in this function because `mgr::get_tenant` will error out after shutdown has
-    // progressed to shutting down tenants.
+    // mean the synthetic size worker should terminate.
     let shutting_down = matches!(
         e.downcast_ref::<PageReconstructError>(),
         Some(PageReconstructError::Cancelled | PageReconstructError::AncestorStopping(_))
diff --git a/pageserver/src/consumption_metrics/metrics.rs b/pageserver/src/consumption_metrics/metrics.rs
index 26b299a71d..6740c1360b 100644
--- a/pageserver/src/consumption_metrics/metrics.rs
+++ b/pageserver/src/consumption_metrics/metrics.rs
@@ -1,3 +1,4 @@
+use crate::tenant::mgr::TenantManager;
 use crate::{context::RequestContext, tenant::timeline::logical_size::CurrentLogicalSize};
 use chrono::{DateTime, Utc};
 use consumption_metrics::EventType;
@@ -181,6 +182,7 @@ impl MetricsKey {
 }
 
 pub(super) async fn collect_all_metrics(
+    tenant_manager: &Arc<TenantManager>,
     cached_metrics: &Cache,
     ctx: &RequestContext,
 ) -> Vec<RawMetric> {
@@ -188,7 +190,7 @@ pub(super) async fn collect_all_metrics(
 
     let started_at = std::time::Instant::now();
 
-    let tenants = match crate::tenant::mgr::list_tenants().await {
+    let tenants = match tenant_manager.list_tenants() {
         Ok(tenants) => tenants,
         Err(err) => {
             tracing::error!("failed to list tenants: {:?}", err);
@@ -200,7 +202,8 @@ pub(super) async fn collect_all_metrics(
         if state != TenantState::Active || !id.is_zero() {
             None
         } else {
-            crate::tenant::mgr::get_tenant(id, true)
+            tenant_manager
+                .get_attached_tenant_shard(id)
                 .ok()
                 .map(|tenant| (id.tenant_id, tenant))
         }
diff --git a/pageserver/src/disk_usage_eviction_task.rs b/pageserver/src/disk_usage_eviction_task.rs
index 92c1475aef..6248424cee 100644
--- a/pageserver/src/disk_usage_eviction_task.rs
+++ b/pageserver/src/disk_usage_eviction_task.rs
@@ -61,7 +61,6 @@ use crate::{
     metrics::disk_usage_based_eviction::METRICS,
     task_mgr::{self, TaskKind, BACKGROUND_RUNTIME},
     tenant::{
-        self,
         mgr::TenantManager,
         remote_timeline_client::LayerFileMetadata,
         secondary::SecondaryTenant,
@@ -814,8 +813,8 @@ async fn collect_eviction_candidates(
     const LOG_DURATION_THRESHOLD: std::time::Duration = std::time::Duration::from_secs(10);
 
     // get a snapshot of the list of tenants
-    let tenants = tenant::mgr::list_tenants()
-        .await
+    let tenants = tenant_manager
+        .list_tenants()
         .context("get list of tenants")?;
 
     // TODO: avoid listing every layer in every tenant: this loop can block the executor,
@@ -827,8 +826,12 @@ async fn collect_eviction_candidates(
         if cancel.is_cancelled() {
             return Ok(EvictionCandidates::Cancelled);
         }
-        let tenant = match tenant::mgr::get_tenant(tenant_id, true) {
-            Ok(tenant) => tenant,
+        let tenant = match tenant_manager.get_attached_tenant_shard(tenant_id) {
+            Ok(tenant) if tenant.is_active() => tenant,
+            Ok(_) => {
+                debug!(tenant_id=%tenant_id.tenant_id, shard_id=%tenant_id.shard_slug(), "Tenant shard is not active");
+                continue;
+            }
             Err(e) => {
                 // this can happen if tenant has lifecycle transition after we fetched it
                 debug!("failed to get tenant: {e:#}");
diff --git a/pageserver/src/http/openapi_spec.yml b/pageserver/src/http/openapi_spec.yml
index 0771229845..bb477f89c5 100644
--- a/pageserver/src/http/openapi_spec.yml
+++ b/pageserver/src/http/openapi_spec.yml
@@ -1038,7 +1038,7 @@ paths:
                   format: hex
       responses:
         "201":
-          description: TimelineInfo
+          description: Timeline was created, or already existed with matching parameters
           content:
             application/json:
               schema:
@@ -1068,11 +1068,17 @@ paths:
               schema:
                 $ref: "#/components/schemas/Error"
         "409":
-          description: Timeline already exists, creation skipped
+          description: Timeline already exists, with different parameters.  Creation cannot proceed.
           content:
             application/json:
               schema:
                 $ref: "#/components/schemas/ConflictError"
+        "429":
+          description: A creation request was sent for the same Timeline Id while a creation was already in progress.  Back off and retry.
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/Error"
         "500":
           description: Generic operation error
           content:
diff --git a/pageserver/src/http/routes.rs b/pageserver/src/http/routes.rs
index 26f23fb8c2..759a1b25ee 100644
--- a/pageserver/src/http/routes.rs
+++ b/pageserver/src/http/routes.rs
@@ -49,8 +49,8 @@ use crate::task_mgr::TaskKind;
 use crate::tenant::config::{LocationConf, TenantConfOpt};
 use crate::tenant::mgr::GetActiveTenantError;
 use crate::tenant::mgr::{
-    GetTenantError, SetNewTenantConfigError, TenantManager, TenantMapError, TenantMapInsertError,
-    TenantSlotError, TenantSlotUpsertError, TenantStateError,
+    GetTenantError, TenantManager, TenantMapError, TenantMapInsertError, TenantSlotError,
+    TenantSlotUpsertError, TenantStateError,
 };
 use crate::tenant::mgr::{TenantSlot, UpsertLocationError};
 use crate::tenant::remote_timeline_client;
@@ -249,16 +249,11 @@ impl From<GetTenantError> for ApiError {
     fn from(tse: GetTenantError) -> ApiError {
         match tse {
             GetTenantError::NotFound(tid) => ApiError::NotFound(anyhow!("tenant {}", tid).into()),
-            GetTenantError::Broken(reason) => {
-                ApiError::InternalServerError(anyhow!("tenant is broken: {}", reason))
-            }
             GetTenantError::NotActive(_) => {
                 // Why is this not `ApiError::NotFound`?
                 // Because we must be careful to never return 404 for a tenant if it does
                 // in fact exist locally. If we did, the caller could draw the conclusion
                 // that it can attach the tenant to another PS and we'd be in split-brain.
-                //
-                // (We can produce this variant only in `mgr::get_tenant(..., active=true)` calls).
                 ApiError::ResourceUnavailable("Tenant not yet active".into())
             }
             GetTenantError::MapState(e) => ApiError::ResourceUnavailable(format!("{e}").into()),
@@ -269,6 +264,9 @@ impl From<GetTenantError> for ApiError {
 impl From<GetActiveTenantError> for ApiError {
     fn from(e: GetActiveTenantError) -> ApiError {
         match e {
+            GetActiveTenantError::Broken(reason) => {
+                ApiError::InternalServerError(anyhow!("tenant is broken: {}", reason))
+            }
             GetActiveTenantError::WillNotBecomeActive(_) => ApiError::Conflict(format!("{}", e)),
             GetActiveTenantError::Cancelled => ApiError::ShuttingDown,
             GetActiveTenantError::NotFound(gte) => gte.into(),
@@ -279,19 +277,6 @@ impl From<GetActiveTenantError> for ApiError {
     }
 }
 
-impl From<SetNewTenantConfigError> for ApiError {
-    fn from(e: SetNewTenantConfigError) -> ApiError {
-        match e {
-            SetNewTenantConfigError::GetTenant(tid) => {
-                ApiError::NotFound(anyhow!("tenant {}", tid).into())
-            }
-            e @ (SetNewTenantConfigError::Persist(_) | SetNewTenantConfigError::Other(_)) => {
-                ApiError::InternalServerError(anyhow::Error::new(e))
-            }
-        }
-    }
-}
-
 impl From<crate::tenant::DeleteTimelineError> for ApiError {
     fn from(value: crate::tenant::DeleteTimelineError) -> Self {
         use crate::tenant::DeleteTimelineError::*;
@@ -495,7 +480,7 @@ async fn timeline_create_handler(
     async {
         let tenant = state
             .tenant_manager
-            .get_attached_tenant_shard(tenant_shard_id, false)?;
+            .get_attached_tenant_shard(tenant_shard_id)?;
 
         tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
 
@@ -535,10 +520,13 @@ async fn timeline_create_handler(
                     HttpErrorBody::from_msg("Tenant shutting down".to_string()),
                 )
             }
-            Err(
-                e @ tenant::CreateTimelineError::Conflict
-                | e @ tenant::CreateTimelineError::AlreadyCreating,
-            ) => json_response(StatusCode::CONFLICT, HttpErrorBody::from_msg(e.to_string())),
+            Err(e @ tenant::CreateTimelineError::Conflict) => {
+                json_response(StatusCode::CONFLICT, HttpErrorBody::from_msg(e.to_string()))
+            }
+            Err(e @ tenant::CreateTimelineError::AlreadyCreating) => json_response(
+                StatusCode::TOO_MANY_REQUESTS,
+                HttpErrorBody::from_msg(e.to_string()),
+            ),
             Err(tenant::CreateTimelineError::AncestorLsn(err)) => json_response(
                 StatusCode::NOT_ACCEPTABLE,
                 HttpErrorBody::from_msg(format!("{err:#}")),
@@ -581,7 +569,7 @@ async fn timeline_list_handler(
     let response_data = async {
         let tenant = state
             .tenant_manager
-            .get_attached_tenant_shard(tenant_shard_id, false)?;
+            .get_attached_tenant_shard(tenant_shard_id)?;
 
         tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
 
@@ -619,6 +607,7 @@ async fn timeline_preserve_initdb_handler(
     let tenant_shard_id: TenantShardId = parse_request_param(&request, "tenant_shard_id")?;
     let timeline_id: TimelineId = parse_request_param(&request, "timeline_id")?;
     check_permission(&request, Some(tenant_shard_id.tenant_id))?;
+    let state = get_state(&request);
 
     // Part of the process for disaster recovery from safekeeper-stored WAL:
     // If we don't recover into a new timeline but want to keep the timeline ID,
@@ -626,7 +615,9 @@ async fn timeline_preserve_initdb_handler(
     // location where timeline recreation cand find it.
 
     async {
-        let tenant = mgr::get_tenant(tenant_shard_id, false)?;
+        let tenant = state
+            .tenant_manager
+            .get_attached_tenant_shard(tenant_shard_id)?;
 
         let timeline = tenant
             .get_timeline(timeline_id, false)
@@ -668,7 +659,7 @@ async fn timeline_detail_handler(
     let timeline_info = async {
         let tenant = state
             .tenant_manager
-            .get_attached_tenant_shard(tenant_shard_id, false)?;
+            .get_attached_tenant_shard(tenant_shard_id)?;
 
         tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
 
@@ -855,7 +846,7 @@ async fn timeline_delete_handler(
 
     let tenant = state
         .tenant_manager
-        .get_attached_tenant_shard(tenant_shard_id, false)
+        .get_attached_tenant_shard(tenant_shard_id)
         .map_err(|e| {
             match e {
                 // GetTenantError has a built-in conversion to ApiError, but in this context we don't
@@ -973,10 +964,11 @@ async fn tenant_list_handler(
     _cancel: CancellationToken,
 ) -> Result<Response<Body>, ApiError> {
     check_permission(&request, None)?;
+    let state = get_state(&request);
 
-    let response_data = mgr::list_tenants()
-        .instrument(info_span!("tenant_list"))
-        .await
+    let response_data = state
+        .tenant_manager
+        .list_tenants()
         .map_err(|_| {
             ApiError::ResourceUnavailable("Tenant map is initializing or shutting down".into())
         })?
@@ -999,9 +991,12 @@ async fn tenant_status(
 ) -> Result<Response<Body>, ApiError> {
     let tenant_shard_id: TenantShardId = parse_request_param(&request, "tenant_shard_id")?;
     check_permission(&request, Some(tenant_shard_id.tenant_id))?;
+    let state = get_state(&request);
 
     let tenant_info = async {
-        let tenant = mgr::get_tenant(tenant_shard_id, false)?;
+        let tenant = state
+            .tenant_manager
+            .get_attached_tenant_shard(tenant_shard_id)?;
 
         // Calculate total physical size of all timelines
         let mut current_physical_size = 0;
@@ -1074,9 +1069,7 @@ async fn tenant_size_handler(
     let inputs_only: Option<bool> = parse_query_param(&request, "inputs_only")?;
     let retention_period: Option<u64> = parse_query_param(&request, "retention_period")?;
     let headers = request.headers();
-
-    let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Download);
-    let tenant = mgr::get_tenant(tenant_shard_id, true)?;
+    let state = get_state(&request);
 
     if !tenant_shard_id.is_zero() {
         return Err(ApiError::BadRequest(anyhow!(
@@ -1084,6 +1077,12 @@ async fn tenant_size_handler(
         )));
     }
 
+    let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Download);
+    let tenant = state
+        .tenant_manager
+        .get_attached_tenant_shard(tenant_shard_id)?;
+    tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
+
     // this can be long operation
     let inputs = tenant
         .gather_size_inputs(
@@ -1152,10 +1151,15 @@ async fn tenant_shard_split_handler(
     let state = get_state(&request);
     let ctx = RequestContext::new(TaskKind::MgmtRequest, DownloadBehavior::Warn);
 
+    let tenant = state
+        .tenant_manager
+        .get_attached_tenant_shard(tenant_shard_id)?;
+    tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
+
     let new_shards = state
         .tenant_manager
         .shard_split(
-            tenant_shard_id,
+            tenant,
             ShardCount::new(req.new_shard_count),
             req.new_stripe_size,
             &ctx,
@@ -1373,8 +1377,11 @@ async fn get_tenant_config_handler(
 ) -> Result<Response<Body>, ApiError> {
     let tenant_shard_id: TenantShardId = parse_request_param(&request, "tenant_shard_id")?;
     check_permission(&request, Some(tenant_shard_id.tenant_id))?;
+    let state = get_state(&request);
 
-    let tenant = mgr::get_tenant(tenant_shard_id, false)?;
+    let tenant = state
+        .tenant_manager
+        .get_attached_tenant_shard(tenant_shard_id)?;
 
     let response = HashMap::from([
         (
@@ -1402,15 +1409,31 @@ async fn update_tenant_config_handler(
     let tenant_id = request_data.tenant_id;
     check_permission(&request, Some(tenant_id))?;
 
-    let tenant_conf =
+    let new_tenant_conf =
         TenantConfOpt::try_from(&request_data.config).map_err(ApiError::BadRequest)?;
 
     let state = get_state(&request);
-    state
+
+    let tenant_shard_id = TenantShardId::unsharded(tenant_id);
+
+    let tenant = state
         .tenant_manager
-        .set_new_tenant_config(tenant_conf, tenant_id)
-        .instrument(info_span!("tenant_config", %tenant_id))
-        .await?;
+        .get_attached_tenant_shard(tenant_shard_id)?;
+    tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
+
+    // This is a legacy API that only operates on attached tenants: the preferred
+    // API to use is the location_config/ endpoint, which lets the caller provide
+    // the full LocationConf.
+    let location_conf = LocationConf::attached_single(
+        new_tenant_conf.clone(),
+        tenant.get_generation(),
+        &ShardParameters::default(),
+    );
+
+    crate::tenant::Tenant::persist_tenant_config(state.conf, &tenant_shard_id, &location_conf)
+        .await
+        .map_err(ApiError::InternalServerError)?;
+    tenant.set_new_tenant_config(new_tenant_conf);
 
     json_response(StatusCode::OK, ())
 }
@@ -1634,10 +1657,12 @@ async fn handle_tenant_break(
 ) -> Result<Response<Body>, ApiError> {
     let tenant_shard_id: TenantShardId = parse_request_param(&r, "tenant_shard_id")?;
 
-    let tenant = crate::tenant::mgr::get_tenant(tenant_shard_id, true)
-        .map_err(|_| ApiError::Conflict(String::from("no active tenant found")))?;
-
-    tenant.set_broken("broken from test".to_owned()).await;
+    let state = get_state(&r);
+    state
+        .tenant_manager
+        .get_attached_tenant_shard(tenant_shard_id)?
+        .set_broken("broken from test".to_owned())
+        .await;
 
     json_response(StatusCode::OK, ())
 }
@@ -1881,7 +1906,7 @@ async fn active_timeline_of_active_tenant(
     tenant_shard_id: TenantShardId,
     timeline_id: TimelineId,
 ) -> Result<Arc<Timeline>, ApiError> {
-    let tenant = tenant_manager.get_attached_tenant_shard(tenant_shard_id, false)?;
+    let tenant = tenant_manager.get_attached_tenant_shard(tenant_shard_id)?;
 
     tenant.wait_to_become_active(ACTIVE_TENANT_TIMEOUT).await?;
 
diff --git a/pageserver/src/page_service.rs b/pageserver/src/page_service.rs
index f3ceb7d3e6..3d622f1871 100644
--- a/pageserver/src/page_service.rs
+++ b/pageserver/src/page_service.rs
@@ -760,6 +760,7 @@ impl PageServerHandler {
         let mut copyin_reader = pin!(StreamReader::new(self.copyin_stream(pgb, &tenant.cancel)));
         timeline
             .import_basebackup_from_tar(
+                tenant.clone(),
                 &mut copyin_reader,
                 base_lsn,
                 self.broker_client.clone(),
diff --git a/pageserver/src/tenant.rs b/pageserver/src/tenant.rs
index dcf9b1a605..792d9e548d 100644
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -1411,7 +1411,7 @@ impl Tenant {
     /// the same timeline ID already exists, returns CreateTimelineError::AlreadyExists.
     #[allow(clippy::too_many_arguments)]
     pub(crate) async fn create_timeline(
-        &self,
+        self: &Arc<Tenant>,
         new_timeline_id: TimelineId,
         ancestor_timeline_id: Option<TimelineId>,
         mut ancestor_start_lsn: Option<Lsn>,
@@ -1559,7 +1559,7 @@ impl Tenant {
             })?;
         }
 
-        loaded_timeline.activate(broker_client, None, ctx);
+        loaded_timeline.activate(self.clone(), broker_client, None, ctx);
 
         Ok(loaded_timeline)
     }
@@ -1731,7 +1731,12 @@ impl Tenant {
             let mut activated_timelines = 0;
 
             for timeline in timelines_to_activate {
-                timeline.activate(broker_client.clone(), background_jobs_can_start, ctx);
+                timeline.activate(
+                    self.clone(),
+                    broker_client.clone(),
+                    background_jobs_can_start,
+                    ctx,
+                );
                 activated_timelines += 1;
             }
 
@@ -2063,7 +2068,12 @@ impl Tenant {
                 TenantState::Active { .. } => {
                     return Ok(());
                 }
-                TenantState::Broken { .. } | TenantState::Stopping { .. } => {
+                TenantState::Broken { reason, .. } => {
+                    // This is fatal, and reported distinctly from the general case of "will never be active" because
+                    // it's logically a 500 to external API users (broken is always a bug).
+                    return Err(GetActiveTenantError::Broken(reason));
+                }
+                TenantState::Stopping { .. } => {
                     // There's no chance the tenant can transition back into ::Active
                     return Err(GetActiveTenantError::WillNotBecomeActive(current_state));
                 }
diff --git a/pageserver/src/tenant/mgr.rs b/pageserver/src/tenant/mgr.rs
index 97a505ded9..f01fb9791c 100644
--- a/pageserver/src/tenant/mgr.rs
+++ b/pageserver/src/tenant/mgr.rs
@@ -4,7 +4,7 @@
 use camino::{Utf8DirEntry, Utf8Path, Utf8PathBuf};
 use itertools::Itertools;
 use pageserver_api::key::Key;
-use pageserver_api::models::{LocationConfigMode, ShardParameters};
+use pageserver_api::models::LocationConfigMode;
 use pageserver_api::shard::{
     ShardCount, ShardIdentity, ShardNumber, ShardStripeSize, TenantShardId,
 };
@@ -16,6 +16,7 @@ use std::collections::{BTreeMap, HashMap};
 use std::ops::Deref;
 use std::sync::Arc;
 use std::time::{Duration, Instant};
+use sysinfo::SystemExt;
 use tokio::fs;
 use utils::timeout::{timeout_cancellable, TimeoutCancellableError};
 
@@ -39,10 +40,10 @@ use crate::metrics::{TENANT, TENANT_MANAGER as METRICS};
 use crate::task_mgr::{self, TaskKind};
 use crate::tenant::config::{
     AttachedLocationConfig, AttachmentMode, LocationConf, LocationMode, SecondaryLocationConfig,
-    TenantConfOpt,
 };
 use crate::tenant::delete::DeleteTenantFlow;
 use crate::tenant::span::debug_assert_current_span_has_tenant_id;
+use crate::tenant::storage_layer::inmemory_layer;
 use crate::tenant::{AttachedTenantConf, SpawnMode, Tenant, TenantState};
 use crate::{InitializationOrder, IGNORED_TENANT_FILE_NAME, METADATA_FILE_NAME, TEMP_FILE_SUFFIX};
 
@@ -543,6 +544,18 @@ pub async fn init_tenant_mgr(
 
     let ctx = RequestContext::todo_child(TaskKind::Startup, DownloadBehavior::Warn);
 
+    // Initialize dynamic limits that depend on system resources
+    let system_memory =
+        sysinfo::System::new_with_specifics(sysinfo::RefreshKind::new().with_memory())
+            .total_memory();
+    let max_ephemeral_layer_bytes =
+        conf.ephemeral_bytes_per_memory_kb as u64 * (system_memory / 1024);
+    tracing::info!("Initialized ephemeral layer size limit to {max_ephemeral_layer_bytes}, for {system_memory} bytes of memory");
+    inmemory_layer::GLOBAL_RESOURCES.max_dirty_bytes.store(
+        max_ephemeral_layer_bytes,
+        std::sync::atomic::Ordering::Relaxed,
+    );
+
     // Scan local filesystem for attached tenants
     let tenant_configs = init_load_tenant_configs(conf).await?;
 
@@ -875,16 +888,6 @@ async fn shutdown_all_tenants0(tenants: &std::sync::RwLock<TenantsMap>) {
     // caller will log how long we took
 }
 
-#[derive(Debug, thiserror::Error)]
-pub(crate) enum SetNewTenantConfigError {
-    #[error(transparent)]
-    GetTenant(#[from] GetTenantError),
-    #[error(transparent)]
-    Persist(anyhow::Error),
-    #[error(transparent)]
-    Other(anyhow::Error),
-}
-
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum UpsertLocationError {
     #[error("Bad config request: {0}")]
@@ -910,32 +913,21 @@ impl TenantManager {
         self.conf
     }
 
-    /// Gets the attached tenant from the in-memory data, erroring if it's absent, in secondary mode, or is not fitting to the query.
-    /// `active_only = true` allows to query only tenants that are ready for operations, erroring on other kinds of tenants.
+    /// Gets the attached tenant from the in-memory data, erroring if it's absent, in secondary mode, or currently
+    /// undergoing a state change (i.e. slot is InProgress).
+    ///
+    /// The return Tenant is not guaranteed to be active: check its status after obtaing it, or
+    /// use [`Tenant::wait_to_become_active`] before using it if you will do I/O on it.
     pub(crate) fn get_attached_tenant_shard(
         &self,
         tenant_shard_id: TenantShardId,
-        active_only: bool,
     ) -> Result<Arc<Tenant>, GetTenantError> {
         let locked = self.tenants.read().unwrap();
 
         let peek_slot = tenant_map_peek_slot(&locked, &tenant_shard_id, TenantSlotPeekMode::Read)?;
 
         match peek_slot {
-            Some(TenantSlot::Attached(tenant)) => match tenant.current_state() {
-                TenantState::Broken {
-                    reason,
-                    backtrace: _,
-                } if active_only => Err(GetTenantError::Broken(reason)),
-                TenantState::Active => Ok(Arc::clone(tenant)),
-                _ => {
-                    if active_only {
-                        Err(GetTenantError::NotActive(tenant_shard_id))
-                    } else {
-                        Ok(Arc::clone(tenant))
-                    }
-                }
-            },
+            Some(TenantSlot::Attached(tenant)) => Ok(Arc::clone(tenant)),
             Some(TenantSlot::InProgress(_)) => Err(GetTenantError::NotActive(tenant_shard_id)),
             None | Some(TenantSlot::Secondary(_)) => {
                 Err(GetTenantError::NotFound(tenant_shard_id.tenant_id))
@@ -1428,7 +1420,8 @@ impl TenantManager {
                     .wait_to_become_active(activation_timeout)
                     .await
                     .map_err(|e| match e {
-                        GetActiveTenantError::WillNotBecomeActive(_) => {
+                        GetActiveTenantError::WillNotBecomeActive(_)
+                        | GetActiveTenantError::Broken(_) => {
                             DeleteTenantError::InvalidState(tenant.current_state())
                         }
                         GetActiveTenantError::Cancelled => DeleteTenantError::Cancelled,
@@ -1455,29 +1448,30 @@ impl TenantManager {
         result
     }
 
-    #[instrument(skip_all, fields(tenant_id=%tenant_shard_id.tenant_id, shard_id=%tenant_shard_id.shard_slug(), new_shard_count=%new_shard_count.literal()))]
+    #[instrument(skip_all, fields(tenant_id=%tenant.get_tenant_shard_id().tenant_id, shard_id=%tenant.get_tenant_shard_id().shard_slug(), new_shard_count=%new_shard_count.literal()))]
     pub(crate) async fn shard_split(
         &self,
-        tenant_shard_id: TenantShardId,
+        tenant: Arc<Tenant>,
         new_shard_count: ShardCount,
         new_stripe_size: Option<ShardStripeSize>,
         ctx: &RequestContext,
     ) -> anyhow::Result<Vec<TenantShardId>> {
+        let tenant_shard_id = *tenant.get_tenant_shard_id();
         let r = self
-            .do_shard_split(tenant_shard_id, new_shard_count, new_stripe_size, ctx)
+            .do_shard_split(tenant, new_shard_count, new_stripe_size, ctx)
             .await;
         if r.is_err() {
             // Shard splitting might have left the original shard in a partially shut down state (it
             // stops the shard's remote timeline client).  Reset it to ensure we leave things in
             // a working state.
             if self.get(tenant_shard_id).is_some() {
-                tracing::warn!("Resetting {tenant_shard_id} after shard split failure");
+                tracing::warn!("Resetting after shard split failure");
                 if let Err(e) = self.reset_tenant(tenant_shard_id, false, ctx).await {
                     // Log this error because our return value will still be the original error, not this one.  This is
                     // a severe error: if this happens, we might be leaving behind a tenant that is not fully functional
                     // (e.g. has uploads disabled).  We can't do anything else: if reset fails then shutting the tenant down or
                     // setting it broken probably won't help either.
-                    tracing::error!("Failed to reset {tenant_shard_id}: {e}");
+                    tracing::error!("Failed to reset: {e}");
                 }
             }
         }
@@ -1487,12 +1481,12 @@ impl TenantManager {
 
     pub(crate) async fn do_shard_split(
         &self,
-        tenant_shard_id: TenantShardId,
+        tenant: Arc<Tenant>,
         new_shard_count: ShardCount,
         new_stripe_size: Option<ShardStripeSize>,
         ctx: &RequestContext,
     ) -> anyhow::Result<Vec<TenantShardId>> {
-        let tenant = get_tenant(tenant_shard_id, true)?;
+        let tenant_shard_id = *tenant.get_tenant_shard_id();
 
         // Validate the incoming request
         if new_shard_count.count() <= tenant_shard_id.shard_count.count() {
@@ -1538,7 +1532,6 @@ impl TenantManager {
             // If [`Tenant::split_prepare`] fails, we must reload the tenant, because it might
             // have been left in a partially-shut-down state.
             tracing::warn!("Failed to prepare for split: {e}, reloading Tenant before returning");
-            self.reset_tenant(tenant_shard_id, false, ctx).await?;
             return Err(e);
         }
 
@@ -1936,38 +1929,23 @@ impl TenantManager {
         removal_result
     }
 
-    pub(crate) async fn set_new_tenant_config(
+    pub(crate) fn list_tenants(
         &self,
-        new_tenant_conf: TenantConfOpt,
-        tenant_id: TenantId,
-    ) -> Result<(), SetNewTenantConfigError> {
-        // Legacy API: does not support sharding
-        let tenant_shard_id = TenantShardId::unsharded(tenant_id);
-
-        info!("configuring tenant {tenant_id}");
-        let tenant = get_tenant(tenant_shard_id, true)?;
-
-        if !tenant.tenant_shard_id().shard_count.is_unsharded() {
-            // Note that we use ShardParameters::default below.
-            return Err(SetNewTenantConfigError::Other(anyhow::anyhow!(
-            "This API may only be used on single-sharded tenants, use the /location_config API for sharded tenants"
-        )));
-        }
-
-        // This is a legacy API that only operates on attached tenants: the preferred
-        // API to use is the location_config/ endpoint, which lets the caller provide
-        // the full LocationConf.
-        let location_conf = LocationConf::attached_single(
-            new_tenant_conf.clone(),
-            tenant.generation,
-            &ShardParameters::default(),
-        );
-
-        Tenant::persist_tenant_config(self.conf, &tenant_shard_id, &location_conf)
-            .await
-            .map_err(SetNewTenantConfigError::Persist)?;
-        tenant.set_new_tenant_config(new_tenant_conf);
-        Ok(())
+    ) -> Result<Vec<(TenantShardId, TenantState, Generation)>, TenantMapListError> {
+        let tenants = TENANTS.read().unwrap();
+        let m = match &*tenants {
+            TenantsMap::Initializing => return Err(TenantMapListError::Initializing),
+            TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m,
+        };
+        Ok(m.iter()
+            .filter_map(|(id, tenant)| match tenant {
+                TenantSlot::Attached(tenant) => {
+                    Some((*id, tenant.current_state(), tenant.generation()))
+                }
+                TenantSlot::Secondary(_) => None,
+                TenantSlot::InProgress(_) => None,
+            })
+            .collect())
     }
 }
 
@@ -1980,51 +1958,12 @@ pub(crate) enum GetTenantError {
 
     #[error("Tenant {0} is not active")]
     NotActive(TenantShardId),
-    /// Broken is logically a subset of NotActive, but a distinct error is useful as
-    /// NotActive is usually a retryable state for API purposes, whereas Broken
-    /// is a stuck error state
-    #[error("Tenant is broken: {0}")]
-    Broken(String),
 
     // Initializing or shutting down: cannot authoritatively say whether we have this tenant
     #[error("Tenant map is not available: {0}")]
     MapState(#[from] TenantMapError),
 }
 
-/// Gets the tenant from the in-memory data, erroring if it's absent or is not fitting to the query.
-/// `active_only = true` allows to query only tenants that are ready for operations, erroring on other kinds of tenants.
-///
-/// This method is cancel-safe.
-pub(crate) fn get_tenant(
-    tenant_shard_id: TenantShardId,
-    active_only: bool,
-) -> Result<Arc<Tenant>, GetTenantError> {
-    let locked = TENANTS.read().unwrap();
-
-    let peek_slot = tenant_map_peek_slot(&locked, &tenant_shard_id, TenantSlotPeekMode::Read)?;
-
-    match peek_slot {
-        Some(TenantSlot::Attached(tenant)) => match tenant.current_state() {
-            TenantState::Broken {
-                reason,
-                backtrace: _,
-            } if active_only => Err(GetTenantError::Broken(reason)),
-            TenantState::Active => Ok(Arc::clone(tenant)),
-            _ => {
-                if active_only {
-                    Err(GetTenantError::NotActive(tenant_shard_id))
-                } else {
-                    Ok(Arc::clone(tenant))
-                }
-            }
-        },
-        Some(TenantSlot::InProgress(_)) => Err(GetTenantError::NotActive(tenant_shard_id)),
-        None | Some(TenantSlot::Secondary(_)) => {
-            Err(GetTenantError::NotFound(tenant_shard_id.tenant_id))
-        }
-    }
-}
-
 #[derive(thiserror::Error, Debug)]
 pub(crate) enum GetActiveTenantError {
     /// We may time out either while TenantSlot is InProgress, or while the Tenant
@@ -2048,6 +1987,12 @@ pub(crate) enum GetActiveTenantError {
     /// Tenant exists, but is in a state that cannot become active (e.g. Stopping, Broken)
     #[error("will not become active.  Current state: {0}")]
     WillNotBecomeActive(TenantState),
+
+    /// Broken is logically a subset of WillNotBecomeActive, but a distinct error is useful as
+    /// WillNotBecomeActive is a permitted error under some circumstances, whereas broken should
+    /// never happen.
+    #[error("Tenant is broken: {0}")]
+    Broken(String),
 }
 
 /// Get a [`Tenant`] in its active state. If the tenant_id is currently in [`TenantSlot::InProgress`]
@@ -2267,27 +2212,6 @@ pub(crate) enum TenantMapListError {
     Initializing,
 }
 
-///
-/// Get list of tenants, for the mgmt API
-///
-pub(crate) async fn list_tenants(
-) -> Result<Vec<(TenantShardId, TenantState, Generation)>, TenantMapListError> {
-    let tenants = TENANTS.read().unwrap();
-    let m = match &*tenants {
-        TenantsMap::Initializing => return Err(TenantMapListError::Initializing),
-        TenantsMap::Open(m) | TenantsMap::ShuttingDown(m) => m,
-    };
-    Ok(m.iter()
-        .filter_map(|(id, tenant)| match tenant {
-            TenantSlot::Attached(tenant) => {
-                Some((*id, tenant.current_state(), tenant.generation()))
-            }
-            TenantSlot::Secondary(_) => None,
-            TenantSlot::InProgress(_) => None,
-        })
-        .collect())
-}
-
 #[derive(Debug, thiserror::Error)]
 pub(crate) enum TenantMapInsertError {
     #[error(transparent)]
diff --git a/pageserver/src/tenant/secondary/heatmap_uploader.rs b/pageserver/src/tenant/secondary/heatmap_uploader.rs
index a8b05f4c0e..39d088ffc3 100644
--- a/pageserver/src/tenant/secondary/heatmap_uploader.rs
+++ b/pageserver/src/tenant/secondary/heatmap_uploader.rs
@@ -9,6 +9,7 @@ use crate::{
     metrics::SECONDARY_MODE,
     tenant::{
         config::AttachmentMode,
+        mgr::GetTenantError,
         mgr::TenantManager,
         remote_timeline_client::remote_heatmap_path,
         span::debug_assert_current_span_has_tenant_id,
@@ -292,8 +293,11 @@ impl JobGenerator<UploadPending, WriteInProgress, WriteComplete, UploadCommand>
             "Starting heatmap write on command");
         let tenant = self
             .tenant_manager
-            .get_attached_tenant_shard(*tenant_shard_id, true)
+            .get_attached_tenant_shard(*tenant_shard_id)
             .map_err(|e| anyhow::anyhow!(e))?;
+        if !tenant.is_active() {
+            return Err(GetTenantError::NotActive(*tenant_shard_id).into());
+        }
 
         Ok(UploadPending {
             // Ignore our state for last digest: this forces an upload even if nothing has changed
diff --git a/pageserver/src/tenant/storage_layer.rs b/pageserver/src/tenant/storage_layer.rs
index 5c3bab9868..f44a92a2d7 100644
--- a/pageserver/src/tenant/storage_layer.rs
+++ b/pageserver/src/tenant/storage_layer.rs
@@ -3,7 +3,7 @@
 pub mod delta_layer;
 mod filename;
 pub mod image_layer;
-mod inmemory_layer;
+pub(crate) mod inmemory_layer;
 pub(crate) mod layer;
 mod layer_desc;
 
diff --git a/pageserver/src/tenant/storage_layer/inmemory_layer.rs b/pageserver/src/tenant/storage_layer/inmemory_layer.rs
index 869d175d8d..628f12065f 100644
--- a/pageserver/src/tenant/storage_layer/inmemory_layer.rs
+++ b/pageserver/src/tenant/storage_layer/inmemory_layer.rs
@@ -89,7 +89,10 @@ impl std::fmt::Debug for InMemoryLayerInner {
 ///
 /// This global state is used to implement behaviors that require a global view of the system, e.g.
 /// rolling layers proactively to limit the total amount of dirty data.
-struct GlobalResources {
+pub(crate) struct GlobalResources {
+    // Limit on how high dirty_bytes may grow before we start freezing layers to reduce it.
+    // Zero means unlimited.
+    pub(crate) max_dirty_bytes: AtomicU64,
     // How many bytes are in all EphemeralFile objects
     dirty_bytes: AtomicU64,
     // How many layers are contributing to dirty_bytes
@@ -118,11 +121,12 @@ impl GlobalResourceUnits {
 
     /// Do not call this frequently: all timelines will write to these same global atomics,
     /// so this is a relatively expensive operation.  Wait at least a few seconds between calls.
-    fn publish_size(&mut self, size: u64) {
+    ///
+    /// Returns the effective layer size limit that should be applied, if any, to keep
+    /// the total number of dirty bytes below the configured maximum.
+    fn publish_size(&mut self, size: u64) -> Option<u64> {
         let new_global_dirty_bytes = match size.cmp(&self.dirty_bytes) {
-            Ordering::Equal => {
-                return;
-            }
+            Ordering::Equal => GLOBAL_RESOURCES.dirty_bytes.load(AtomicOrdering::Relaxed),
             Ordering::Greater => {
                 let delta = size - self.dirty_bytes;
                 let old = GLOBAL_RESOURCES
@@ -146,6 +150,21 @@ impl GlobalResourceUnits {
         TIMELINE_EPHEMERAL_BYTES.set(new_global_dirty_bytes);
 
         self.dirty_bytes = size;
+
+        let max_dirty_bytes = GLOBAL_RESOURCES
+            .max_dirty_bytes
+            .load(AtomicOrdering::Relaxed);
+        if max_dirty_bytes > 0 && new_global_dirty_bytes > max_dirty_bytes {
+            // Set the layer file limit to the average layer size: this implies that all above-average
+            // sized layers will be elegible for freezing.  They will be frozen in the order they
+            // next enter publish_size.
+            Some(
+                new_global_dirty_bytes
+                    / GLOBAL_RESOURCES.dirty_layers.load(AtomicOrdering::Relaxed) as u64,
+            )
+        } else {
+            None
+        }
     }
 
     // Call publish_size if the input size differs from last published size by more than
@@ -174,7 +193,8 @@ impl Drop for GlobalResourceUnits {
     }
 }
 
-static GLOBAL_RESOURCES: GlobalResources = GlobalResources {
+pub(crate) static GLOBAL_RESOURCES: GlobalResources = GlobalResources {
+    max_dirty_bytes: AtomicU64::new(0),
     dirty_bytes: AtomicU64::new(0),
     dirty_layers: AtomicUsize::new(0),
 };
@@ -194,6 +214,10 @@ impl InMemoryLayer {
         }
     }
 
+    pub(crate) fn try_len(&self) -> Option<u64> {
+        self.inner.try_read().map(|i| i.file.len()).ok()
+    }
+
     pub(crate) fn assert_writable(&self) {
         assert!(self.end_lsn.get().is_none());
     }
@@ -486,10 +510,10 @@ impl InMemoryLayer {
         Ok(())
     }
 
-    pub(crate) async fn tick(&self) {
+    pub(crate) async fn tick(&self) -> Option<u64> {
         let mut inner = self.inner.write().await;
         let size = inner.file.len();
-        inner.resource_units.publish_size(size);
+        inner.resource_units.publish_size(size)
     }
 
     pub(crate) async fn put_tombstones(&self, _key_ranges: &[(Range<Key>, Lsn)]) -> Result<()> {
diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 0b8cdac1cc..bc3fc1df1f 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -19,7 +19,7 @@ use pageserver_api::{
     keyspace::KeySpaceAccum,
     models::{
         CompactionAlgorithm, DownloadRemoteLayersTaskInfo, DownloadRemoteLayersTaskSpawnRequest,
-        EvictionPolicy, LayerMapInfo, TimelineState,
+        EvictionPolicy, InMemoryLayerInfo, LayerMapInfo, TimelineState,
     },
     reltag::BlockNumber,
     shard::{ShardIdentity, TenantShardId},
@@ -1142,6 +1142,79 @@ impl Timeline {
         self.flush_frozen_layers_and_wait().await
     }
 
+    /// If there is no writer, and conditions for rolling the latest layer are met, then freeze it.
+    ///
+    /// This is for use in background housekeeping, to provide guarantees of layers closing eventually
+    /// even if there are no ongoing writes to drive that.
+    async fn maybe_freeze_ephemeral_layer(&self) {
+        let Ok(_write_guard) = self.write_lock.try_lock() else {
+            // If the write lock is held, there is an active wal receiver: rolling open layers
+            // is their responsibility while they hold this lock.
+            return;
+        };
+
+        let Ok(layers_guard) = self.layers.try_read() else {
+            // Don't block if the layer lock is busy
+            return;
+        };
+
+        let Some(open_layer) = &layers_guard.layer_map().open_layer else {
+            // No open layer, no work to do.
+            return;
+        };
+
+        let Some(current_size) = open_layer.try_len() else {
+            // Unexpected: since we hold the write guard, nobody else should be writing to this layer, so
+            // read lock to get size should always succeed.
+            tracing::warn!("Lock conflict while reading size of open layer");
+            return;
+        };
+
+        let current_lsn = self.get_last_record_lsn();
+
+        let checkpoint_distance_override = open_layer.tick().await;
+
+        if let Some(size_override) = checkpoint_distance_override {
+            if current_size > size_override {
+                // This is not harmful, but it only happens in relatively rare cases where
+                // time-based checkpoints are not happening fast enough to keep the amount of
+                // ephemeral data within configured limits.  It's a sign of stress on the system.
+                tracing::info!("Early-rolling open layer at size {current_size} (limit {size_override}) due to dirty data pressure");
+            }
+        }
+
+        let checkpoint_distance =
+            checkpoint_distance_override.unwrap_or(self.get_checkpoint_distance());
+
+        if self.should_roll(
+            current_size,
+            current_size,
+            checkpoint_distance,
+            self.get_last_record_lsn(),
+            self.last_freeze_at.load(),
+            *self.last_freeze_ts.read().unwrap(),
+        ) {
+            match open_layer.info() {
+                InMemoryLayerInfo::Frozen { lsn_start, lsn_end } => {
+                    // We may reach this point if the layer was already frozen by not yet flushed: flushing
+                    // happens asynchronously in the background.
+                    tracing::debug!(
+                        "Not freezing open layer, it's already frozen ({lsn_start}..{lsn_end})"
+                    );
+                }
+                InMemoryLayerInfo::Open { .. } => {
+                    // Upgrade to a write lock and freeze the layer
+                    drop(layers_guard);
+                    let mut layers_guard = self.layers.write().await;
+                    layers_guard
+                        .try_freeze_in_memory_layer(current_lsn, &self.last_freeze_at)
+                        .await;
+                }
+            }
+            self.flush_frozen_layers();
+        }
+    }
+
     /// Outermost timeline compaction operation; downloads needed layers.
     pub(crate) async fn compact(
         self: &Arc<Self>,
@@ -1164,6 +1237,11 @@ impl Timeline {
             (guard, permit)
         };
 
+        // Prior to compaction, check if an open ephemeral layer should be closed: this provides
+        // background enforcement of checkpoint interval if there is no active WAL receiver, to avoid keeping
+        // an ephemeral layer open forever when idle.
+        self.maybe_freeze_ephemeral_layer().await;
+
         // this wait probably never needs any "long time spent" logging, because we already nag if
         // compaction task goes over it's period (20s) which is quite often in production.
         let (_guard, _permit) = tokio::select! {
@@ -1196,6 +1274,7 @@ impl Timeline {
 
     pub(crate) fn activate(
         self: &Arc<Self>,
+        parent: Arc<crate::tenant::Tenant>,
         broker_client: BrokerClientChannel,
         background_jobs_can_start: Option<&completion::Barrier>,
         ctx: &RequestContext,
@@ -1206,7 +1285,7 @@ impl Timeline {
         }
         self.launch_wal_receiver(ctx, broker_client);
         self.set_state(TimelineState::Active);
-        self.launch_eviction_task(background_jobs_can_start);
+        self.launch_eviction_task(parent, background_jobs_can_start);
     }
 
     /// Graceful shutdown, may do a lot of I/O as we flush any open layers to disk and then
@@ -1434,6 +1513,53 @@ impl Timeline {
             Err(EvictionError::Timeout) => Ok(Some(false)),
         }
     }
+
+    fn should_roll(
+        &self,
+        layer_size: u64,
+        projected_layer_size: u64,
+        checkpoint_distance: u64,
+        projected_lsn: Lsn,
+        last_freeze_at: Lsn,
+        last_freeze_ts: Instant,
+    ) -> bool {
+        let distance = projected_lsn.widening_sub(last_freeze_at);
+
+        // Rolling the open layer can be triggered by:
+        // 1. The distance from the last LSN we rolled at. This bounds the amount of WAL that
+        //    the safekeepers need to store.  For sharded tenants, we multiply by shard count to
+        //    account for how writes are distributed across shards: we expect each node to consume
+        //    1/count of the LSN on average.
+        // 2. The size of the currently open layer.
+        // 3. The time since the last roll. It helps safekeepers to regard pageserver as caught
+        //    up and suspend activity.
+        if distance >= checkpoint_distance as i128 * self.shard_identity.count.count() as i128 {
+            info!(
+                "Will roll layer at {} with layer size {} due to LSN distance ({})",
+                projected_lsn, layer_size, distance
+            );
+
+            true
+        } else if projected_layer_size >= checkpoint_distance {
+            info!(
+                "Will roll layer at {} with layer size {} due to layer size ({})",
+                projected_lsn, layer_size, projected_layer_size
+            );
+
+            true
+        } else if distance > 0 && last_freeze_ts.elapsed() >= self.get_checkpoint_timeout() {
+            info!(
+                "Will roll layer at {} with layer size {} due to time since last flush ({:?})",
+                projected_lsn,
+                layer_size,
+                last_freeze_ts.elapsed()
+            );
+
+            true
+        } else {
+            false
+        }
+    }
 }
 
 /// Number of times we will compute partition within a checkpoint distance.
@@ -2587,6 +2713,10 @@ impl Timeline {
                     // Get all the data needed to reconstruct the page version from this layer.
                     // But if we have an older cached page image, no need to go past that.
                     let lsn_floor = max(cached_lsn + 1, start_lsn);
+
+                    let open_layer = open_layer.clone();
+                    drop(guard);
+
                     result = match open_layer
                         .get_value_reconstruct_data(
                             key,
@@ -2604,10 +2734,7 @@ impl Timeline {
                     traversal_path.push((
                         result,
                         cont_lsn,
-                        Box::new({
-                            let open_layer = Arc::clone(open_layer);
-                            move || open_layer.traversal_id()
-                        }),
+                        Box::new(move || open_layer.traversal_id()),
                     ));
                     continue 'outer;
                 }
@@ -2617,6 +2744,10 @@ impl Timeline {
                 if cont_lsn > start_lsn {
                     //info!("CHECKING for {} at {} on frozen layer {}", key, cont_lsn, frozen_layer.filename().display());
                     let lsn_floor = max(cached_lsn + 1, start_lsn);
+
+                    let frozen_layer = frozen_layer.clone();
+                    drop(guard);
+
                     result = match frozen_layer
                         .get_value_reconstruct_data(
                             key,
@@ -2634,10 +2765,7 @@ impl Timeline {
                     traversal_path.push((
                         result,
                         cont_lsn,
-                        Box::new({
-                            let frozen_layer = Arc::clone(frozen_layer);
-                            move || frozen_layer.traversal_id()
-                        }),
+                        Box::new(move || frozen_layer.traversal_id()),
                     ));
                     continue 'outer;
                 }
@@ -2645,6 +2773,8 @@ impl Timeline {
 
             if let Some(SearchResult { lsn_floor, layer }) = layers.search(key, cont_lsn) {
                 let layer = guard.get_from_desc(&layer);
+                drop(guard);
+
                 // Get all the data needed to reconstruct the page version from this layer.
                 // But if we have an older cached page image, no need to go past that.
                 let lsn_floor = max(cached_lsn + 1, lsn_floor);
@@ -4451,52 +4581,6 @@ impl<'a> TimelineWriter<'a> {
         res
     }
 
-    /// "Tick" the timeline writer: it will roll the open layer if required
-    /// and do nothing else.
-    pub(crate) async fn tick(&mut self) -> anyhow::Result<()> {
-        self.open_layer_if_present().await?;
-
-        let last_record_lsn = self.get_last_record_lsn();
-        let action = self.get_open_layer_action(last_record_lsn, 0);
-        if action == OpenLayerAction::Roll {
-            self.roll_layer(last_record_lsn).await?;
-        } else if let Some(writer_state) = &mut *self.write_guard {
-            // Periodic update of statistics
-            writer_state.open_layer.tick().await;
-        }
-
-        Ok(())
-    }
-
-    /// Populate the timeline writer state only if an in-memory layer
-    /// is already open.
-    async fn open_layer_if_present(&mut self) -> anyhow::Result<()> {
-        assert!(self.write_guard.is_none());
-
-        let open_layer = {
-            let guard = self.layers.read().await;
-            let layers = guard.layer_map();
-            match layers.open_layer {
-                Some(ref open_layer) => open_layer.clone(),
-                None => {
-                    return Ok(());
-                }
-            }
-        };
-
-        let initial_size = open_layer.size().await?;
-        let last_freeze_at = self.last_freeze_at.load();
-        let last_freeze_ts = *self.last_freeze_ts.read().unwrap();
-        self.write_guard.replace(TimelineWriterState::new(
-            open_layer,
-            initial_size,
-            last_freeze_at,
-            last_freeze_ts,
-        ));
-
-        Ok(())
-    }
-
     async fn handle_open_layer_action(
         &mut self,
         at: Lsn,
@@ -4568,43 +4652,14 @@ impl<'a> TimelineWriter<'a> {
             return OpenLayerAction::None;
         }
 
-        let distance = lsn.widening_sub(state.cached_last_freeze_at);
-        let proposed_open_layer_size = state.current_size + new_value_size;
-
-        // Rolling the open layer can be triggered by:
-        // 1. The distance from the last LSN we rolled at. This bounds the amount of WAL that
-        //    the safekeepers need to store.  For sharded tenants, we multiply by shard count to
-        //    account for how writes are distributed across shards: we expect each node to consume
-        //    1/count of the LSN on average.
-        // 2. The size of the currently open layer.
-        // 3. The time since the last roll. It helps safekeepers to regard pageserver as caught
-        //    up and suspend activity.
-        if distance
-            >= self.get_checkpoint_distance() as i128 * self.shard_identity.count.count() as i128
-        {
-            info!(
-                "Will roll layer at {} with layer size {} due to LSN distance ({})",
-                lsn, state.current_size, distance
-            );
-
-            OpenLayerAction::Roll
-        } else if proposed_open_layer_size >= self.get_checkpoint_distance() {
-            info!(
-                "Will roll layer at {} with layer size {} due to layer size ({})",
-                lsn, state.current_size, proposed_open_layer_size
-            );
-
-            OpenLayerAction::Roll
-        } else if distance > 0
-            && state.cached_last_freeze_ts.elapsed() >= self.get_checkpoint_timeout()
-        {
-            info!(
-                "Will roll layer at {} with layer size {} due to time since last flush ({:?})",
-                lsn,
-                state.current_size,
-                state.cached_last_freeze_ts.elapsed()
-            );
-
+        if self.tl.should_roll(
+            state.current_size,
+            state.current_size + new_value_size,
+            self.get_checkpoint_distance(),
+            lsn,
+            state.cached_last_freeze_at,
+            state.cached_last_freeze_ts,
+        ) {
             OpenLayerAction::Roll
         } else {
             OpenLayerAction::None
diff --git a/pageserver/src/tenant/timeline/eviction_task.rs b/pageserver/src/tenant/timeline/eviction_task.rs
index dd769d4121..ebcd70bd39 100644
--- a/pageserver/src/tenant/timeline/eviction_task.rs
+++ b/pageserver/src/tenant/timeline/eviction_task.rs
@@ -51,6 +51,7 @@ pub struct EvictionTaskTenantState {
 impl Timeline {
     pub(super) fn launch_eviction_task(
         self: &Arc<Self>,
+        parent: Arc<Tenant>,
         background_tasks_can_start: Option<&completion::Barrier>,
     ) {
         let self_clone = Arc::clone(self);
@@ -72,14 +73,14 @@ impl Timeline {
                     _ = completion::Barrier::maybe_wait(background_tasks_can_start) => {}
                 };
 
-                self_clone.eviction_task(cancel).await;
+                self_clone.eviction_task(parent, cancel).await;
                 Ok(())
             },
         );
     }
 
     #[instrument(skip_all, fields(tenant_id = %self.tenant_shard_id.tenant_id, shard_id = %self.tenant_shard_id.shard_slug(), timeline_id = %self.timeline_id))]
-    async fn eviction_task(self: Arc<Self>, cancel: CancellationToken) {
+    async fn eviction_task(self: Arc<Self>, tenant: Arc<Tenant>, cancel: CancellationToken) {
         use crate::tenant::tasks::random_init_delay;
 
         // acquire the gate guard only once within a useful span
@@ -103,7 +104,7 @@ impl Timeline {
         loop {
             let policy = self.get_eviction_policy();
             let cf = self
-                .eviction_iteration(&policy, &cancel, &guard, &ctx)
+                .eviction_iteration(&tenant, &policy, &cancel, &guard, &ctx)
                 .await;
 
             match cf {
@@ -123,6 +124,7 @@ impl Timeline {
     #[instrument(skip_all, fields(policy_kind = policy.discriminant_str()))]
     async fn eviction_iteration(
         self: &Arc<Self>,
+        tenant: &Tenant,
         policy: &EvictionPolicy,
         cancel: &CancellationToken,
         gate: &GateGuard,
@@ -137,7 +139,7 @@ impl Timeline {
             }
             EvictionPolicy::LayerAccessThreshold(p) => {
                 match self
-                    .eviction_iteration_threshold(p, cancel, gate, ctx)
+                    .eviction_iteration_threshold(tenant, p, cancel, gate, ctx)
                     .await
                 {
                     ControlFlow::Break(()) => return ControlFlow::Break(()),
@@ -146,7 +148,11 @@ impl Timeline {
                 (p.period, p.threshold)
             }
             EvictionPolicy::OnlyImitiate(p) => {
-                if self.imitiate_only(p, cancel, gate, ctx).await.is_break() {
+                if self
+                    .imitiate_only(tenant, p, cancel, gate, ctx)
+                    .await
+                    .is_break()
+                {
                     return ControlFlow::Break(());
                 }
                 (p.period, p.threshold)
@@ -175,6 +181,7 @@ impl Timeline {
 
     async fn eviction_iteration_threshold(
         self: &Arc<Self>,
+        tenant: &Tenant,
         p: &EvictionPolicyLayerAccessThreshold,
         cancel: &CancellationToken,
         gate: &GateGuard,
@@ -193,7 +200,10 @@ impl Timeline {
             _ = self.cancel.cancelled() => return ControlFlow::Break(()),
         };
 
-        match self.imitate_layer_accesses(p, cancel, gate, ctx).await {
+        match self
+            .imitate_layer_accesses(tenant, p, cancel, gate, ctx)
+            .await
+        {
             ControlFlow::Break(()) => return ControlFlow::Break(()),
             ControlFlow::Continue(()) => (),
         }
@@ -315,6 +325,7 @@ impl Timeline {
     /// disk usage based eviction task.
     async fn imitiate_only(
         self: &Arc<Self>,
+        tenant: &Tenant,
         p: &EvictionPolicyLayerAccessThreshold,
         cancel: &CancellationToken,
         gate: &GateGuard,
@@ -331,7 +342,8 @@ impl Timeline {
             _ = self.cancel.cancelled() => return ControlFlow::Break(()),
         };
 
-        self.imitate_layer_accesses(p, cancel, gate, ctx).await
+        self.imitate_layer_accesses(tenant, p, cancel, gate, ctx)
+            .await
     }
 
     /// If we evict layers but keep cached values derived from those layers, then
@@ -361,6 +373,7 @@ impl Timeline {
     #[instrument(skip_all)]
     async fn imitate_layer_accesses(
         &self,
+        tenant: &Tenant,
         p: &EvictionPolicyLayerAccessThreshold,
         cancel: &CancellationToken,
         gate: &GateGuard,
@@ -396,17 +409,11 @@ impl Timeline {
         // Make one of the tenant's timelines draw the short straw and run the calculation.
         // The others wait until the calculation is done so that they take into account the
         // imitated accesses that the winner made.
-        let tenant = match crate::tenant::mgr::get_tenant(self.tenant_shard_id, true) {
-            Ok(t) => t,
-            Err(_) => {
-                return ControlFlow::Break(());
-            }
-        };
         let mut state = tenant.eviction_task_tenant_state.lock().await;
         match state.last_layer_access_imitation {
             Some(ts) if ts.elapsed() < inter_imitate_period => { /* no need to run */ }
             _ => {
-                self.imitate_synthetic_size_calculation_worker(&tenant, cancel, ctx)
+                self.imitate_synthetic_size_calculation_worker(tenant, cancel, ctx)
                     .await;
                 state.last_layer_access_imitation = Some(tokio::time::Instant::now());
             }
@@ -480,7 +487,7 @@ impl Timeline {
     #[instrument(skip_all)]
     async fn imitate_synthetic_size_calculation_worker(
         &self,
-        tenant: &Arc<Tenant>,
+        tenant: &Tenant,
         cancel: &CancellationToken,
         ctx: &RequestContext,
     ) {
diff --git a/pageserver/src/tenant/timeline/uninit.rs b/pageserver/src/tenant/timeline/uninit.rs
index e1034a9fe2..2b60e670ea 100644
--- a/pageserver/src/tenant/timeline/uninit.rs
+++ b/pageserver/src/tenant/timeline/uninit.rs
@@ -86,6 +86,7 @@ impl<'t> UninitializedTimeline<'t> {
     /// Prepares timeline data by loading it from the basebackup archive.
     pub(crate) async fn import_basebackup_from_tar(
         self,
+        tenant: Arc<Tenant>,
         copyin_read: &mut (impl tokio::io::AsyncRead + Send + Sync + Unpin),
         base_lsn: Lsn,
         broker_client: storage_broker::BrokerClientChannel,
@@ -114,7 +115,7 @@ impl<'t> UninitializedTimeline<'t> {
 
         // All the data has been imported. Insert the Timeline into the tenant's timelines map
         let tl = self.finish_creation()?;
-        tl.activate(broker_client, None, ctx);
+        tl.activate(tenant, broker_client, None, ctx);
         Ok(tl)
     }
 
diff --git a/pageserver/src/tenant/timeline/walreceiver.rs b/pageserver/src/tenant/timeline/walreceiver.rs
index 2fab6722b8..f1b62067f9 100644
--- a/pageserver/src/tenant/timeline/walreceiver.rs
+++ b/pageserver/src/tenant/timeline/walreceiver.rs
@@ -33,11 +33,9 @@ use crate::tenant::timeline::walreceiver::connection_manager::{
 use pageserver_api::shard::TenantShardId;
 use std::future::Future;
 use std::num::NonZeroU64;
-use std::ops::ControlFlow;
 use std::sync::Arc;
 use std::time::Duration;
 use storage_broker::BrokerClientChannel;
-use tokio::select;
 use tokio::sync::watch;
 use tokio_util::sync::CancellationToken;
 use tracing::*;
@@ -91,31 +89,27 @@ impl WalReceiver {
             async move {
                 debug_assert_current_span_has_tenant_and_timeline_id();
                 debug!("WAL receiver manager started, connecting to broker");
+                let cancel = task_mgr::shutdown_token();
                 let mut connection_manager_state = ConnectionManagerState::new(
                     timeline,
                     conf,
                 );
-                loop {
-                    select! {
-                        _ = task_mgr::shutdown_watcher() => {
-                            trace!("WAL receiver shutdown requested, shutting down");
+                while !cancel.is_cancelled() {
+                    let loop_step_result = connection_manager_loop_step(
+                        &mut broker_client,
+                        &mut connection_manager_state,
+                        &walreceiver_ctx,
+                        &cancel,
+                        &loop_status,
+                    ).await;
+                    match loop_step_result {
+                        Ok(()) => continue,
+                        Err(_cancelled) => {
+                            trace!("Connection manager loop ended, shutting down");
                             break;
-                        },
-                        loop_step_result = connection_manager_loop_step(
-                            &mut broker_client,
-                            &mut connection_manager_state,
-                            &walreceiver_ctx,
-                            &loop_status,
-                        ) => match loop_step_result {
-                            ControlFlow::Continue(()) => continue,
-                            ControlFlow::Break(()) => {
-                                trace!("Connection manager loop ended, shutting down");
-                                break;
-                            }
-                        },
+                        }
                     }
                 }
-
                 connection_manager_state.shutdown().await;
                 *loop_status.write().unwrap() = None;
                 Ok(())
@@ -197,6 +191,9 @@ impl<E: Clone> TaskHandle<E> {
         }
     }
 
+    /// # Cancel-Safety
+    ///
+    /// Cancellation-safe.
     async fn next_task_event(&mut self) -> TaskEvent<E> {
         match self.events_receiver.changed().await {
             Ok(()) => TaskEvent::Update((self.events_receiver.borrow()).clone()),
diff --git a/pageserver/src/tenant/timeline/walreceiver/connection_manager.rs b/pageserver/src/tenant/timeline/walreceiver/connection_manager.rs
index cf6dee114f..030d24a017 100644
--- a/pageserver/src/tenant/timeline/walreceiver/connection_manager.rs
+++ b/pageserver/src/tenant/timeline/walreceiver/connection_manager.rs
@@ -17,7 +17,7 @@ use crate::metrics::{
     WALRECEIVER_ACTIVE_MANAGERS, WALRECEIVER_BROKER_UPDATES, WALRECEIVER_CANDIDATES_ADDED,
     WALRECEIVER_CANDIDATES_REMOVED, WALRECEIVER_SWITCHES,
 };
-use crate::task_mgr::{shutdown_token, TaskKind};
+use crate::task_mgr::TaskKind;
 use crate::tenant::{debug_assert_current_span_has_tenant_and_timeline_id, Timeline};
 use anyhow::Context;
 use chrono::{NaiveDateTime, Utc};
@@ -27,7 +27,7 @@ use storage_broker::proto::SafekeeperTimelineInfo;
 use storage_broker::proto::SubscribeSafekeeperInfoRequest;
 use storage_broker::proto::TenantTimelineId as ProtoTenantTimelineId;
 use storage_broker::{BrokerClientChannel, Code, Streaming};
-use tokio::select;
+use tokio_util::sync::CancellationToken;
 use tracing::*;
 
 use postgres_connection::PgConnectionConfig;
@@ -45,27 +45,33 @@ use super::{
     TaskEvent, TaskHandle,
 };
 
+pub(crate) struct Cancelled;
+
 /// Attempts to subscribe for timeline updates, pushed by safekeepers into the broker.
 /// Based on the updates, desides whether to start, keep or stop a WAL receiver task.
 /// If storage broker subscription is cancelled, exits.
+///
+/// # Cancel-Safety
+///
+/// Not cancellation-safe. Use `cancel` token to request cancellation.
 pub(super) async fn connection_manager_loop_step(
     broker_client: &mut BrokerClientChannel,
     connection_manager_state: &mut ConnectionManagerState,
     ctx: &RequestContext,
+    cancel: &CancellationToken,
     manager_status: &std::sync::RwLock<Option<ConnectionManagerStatus>>,
-) -> ControlFlow<(), ()> {
-    match connection_manager_state
-        .timeline
-        .wait_to_become_active(ctx)
-        .await
-    {
+) -> Result<(), Cancelled> {
+    match tokio::select! {
+        _ = cancel.cancelled() => { return Err(Cancelled); },
+        st = connection_manager_state.timeline.wait_to_become_active(ctx) => { st }
+    } {
         Ok(()) => {}
         Err(new_state) => {
             debug!(
                 ?new_state,
                 "state changed, stopping wal connection manager loop"
             );
-            return ControlFlow::Break(());
+            return Err(Cancelled);
         }
     }
 
@@ -86,7 +92,7 @@ pub(super) async fn connection_manager_loop_step(
     // Subscribe to the broker updates. Stream shares underlying TCP connection
     // with other streams on this client (other connection managers). When
     // object goes out of scope, stream finishes in drop() automatically.
-    let mut broker_subscription = subscribe_for_timeline_updates(broker_client, id).await;
+    let mut broker_subscription = subscribe_for_timeline_updates(broker_client, id, cancel).await?;
     debug!("Subscribed for broker timeline updates");
 
     loop {
@@ -94,6 +100,7 @@ pub(super) async fn connection_manager_loop_step(
 
         // These things are happening concurrently:
         //
+        // - cancellation request
         //  - keep receiving WAL on the current connection
         //      - if the shared state says we need to change connection, disconnect and return
         //      - this runs in a separate task and we receive updates via a watch channel
@@ -101,7 +108,11 @@ pub(super) async fn connection_manager_loop_step(
         //  - receive updates from broker
         //      - this might change the current desired connection
         //  - timeline state changes to something that does not allow walreceiver to run concurrently
-        select! {
+
+        // NB: make sure each of the select expressions are cancellation-safe
+        // (no need for arms to be cancellation-safe).
+        tokio::select! {
+            _ = cancel.cancelled() => { return Err(Cancelled); }
             Some(wal_connection_update) = async {
                 match connection_manager_state.wal_connection.as_mut() {
                     Some(wal_connection) => Some(wal_connection.connection_task.next_task_event().await),
@@ -133,7 +144,7 @@ pub(super) async fn connection_manager_loop_step(
             },
 
             // Got a new update from the broker
-            broker_update = broker_subscription.message() => {
+            broker_update = broker_subscription.message() /* TODO: review cancellation-safety */ => {
                 match broker_update {
                     Ok(Some(broker_update)) => connection_manager_state.register_timeline_update(broker_update),
                     Err(status) => {
@@ -147,16 +158,17 @@ pub(super) async fn connection_manager_loop_step(
                                 warn!("broker subscription failed: {status}");
                             }
                         }
-                        return ControlFlow::Continue(());
+                        return Ok(());
                     }
                     Ok(None) => {
                         error!("broker subscription stream ended"); // can't happen
-                        return ControlFlow::Continue(());
+                        return Ok(());
                     }
                 }
             },
 
             new_event = async {
+                // Reminder: this match arm needs to be cancellation-safe.
                 loop {
                     if connection_manager_state.timeline.current_state() == TimelineState::Loading {
                         warn!("wal connection manager should only be launched after timeline has become active");
@@ -182,11 +194,11 @@ pub(super) async fn connection_manager_loop_step(
                 }
             } => match new_event {
                 ControlFlow::Continue(()) => {
-                    return ControlFlow::Continue(());
+                    return Ok(());
                 }
                 ControlFlow::Break(()) => {
                     debug!("Timeline is no longer active, stopping wal connection manager loop");
-                    return ControlFlow::Break(());
+                    return Err(Cancelled);
                 }
             },
 
@@ -218,16 +230,15 @@ pub(super) async fn connection_manager_loop_step(
 async fn subscribe_for_timeline_updates(
     broker_client: &mut BrokerClientChannel,
     id: TenantTimelineId,
-) -> Streaming<SafekeeperTimelineInfo> {
+    cancel: &CancellationToken,
+) -> Result<Streaming<SafekeeperTimelineInfo>, Cancelled> {
     let mut attempt = 0;
-    let cancel = shutdown_token();
-
     loop {
         exponential_backoff(
             attempt,
             DEFAULT_BASE_BACKOFF_SECONDS,
             DEFAULT_MAX_BACKOFF_SECONDS,
-            &cancel,
+            cancel,
         )
         .await;
         attempt += 1;
@@ -241,9 +252,14 @@ async fn subscribe_for_timeline_updates(
             subscription_key: Some(key),
         };
 
-        match broker_client.subscribe_safekeeper_info(request).await {
+        match {
+            tokio::select! {
+                r = broker_client.subscribe_safekeeper_info(request) => { r }
+                _ = cancel.cancelled() => { return Err(Cancelled); }
+            }
+        } {
             Ok(resp) => {
-                return resp.into_inner();
+                return Ok(resp.into_inner());
             }
             Err(e) => {
                 // Safekeeper nodes can stop pushing timeline updates to the broker, when no new writes happen and
@@ -486,6 +502,10 @@ impl ConnectionManagerState {
 
     /// Drops the current connection (if any) and updates retry timeout for the next
     /// connection attempt to the same safekeeper.
+    ///
+    /// # Cancel-Safety
+    ///
+    /// Not cancellation-safe.
     async fn drop_old_connection(&mut self, needs_shutdown: bool) {
         let wal_connection = match self.wal_connection.take() {
             Some(wal_connection) => wal_connection,
@@ -493,7 +513,14 @@ impl ConnectionManagerState {
         };
 
         if needs_shutdown {
-            wal_connection.connection_task.shutdown().await;
+            wal_connection
+                .connection_task
+                .shutdown()
+                // This here is why this function isn't cancellation-safe.
+                // If we got cancelled here, then self.wal_connection is already None and we lose track of the task.
+                // Even if our caller diligently calls Self::shutdown(), it will find a self.wal_connection=None
+                // and thus be ineffective.
+                .await;
         }
 
         let retry = self
@@ -838,6 +865,9 @@ impl ConnectionManagerState {
         }
     }
 
+    /// # Cancel-Safety
+    ///
+    /// Not cancellation-safe.
     pub(super) async fn shutdown(mut self) {
         if let Some(wal_connection) = self.wal_connection.take() {
             wal_connection.connection_task.shutdown().await;
diff --git a/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs b/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
index d9f780cfd1..00a9dbd760 100644
--- a/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
+++ b/pageserver/src/tenant/timeline/walreceiver/walreceiver_connection.rs
@@ -389,17 +389,6 @@ pub(super) async fn handle_walreceiver_connection(
             }
         }
 
-        {
-            // This is a hack. It piggybacks on the keepalive messages sent by the
-            // safekeeper in order to enforce `checkpoint_timeout` on the currently
-            // open layer. This hack doesn't provide a bound on the total size of
-            // in-memory layers on a pageserver. See https://github.com/neondatabase/neon/issues/6916.
-            let mut writer = timeline.writer().await;
-            if let Err(err) = writer.tick().await {
-                warn!("Timeline writer tick failed: {err}");
-            }
-        }
-
         if let Some(last_lsn) = status_update {
             let timeline_remote_consistent_lsn = timeline
                 .get_remote_consistent_lsn_visible()
diff --git a/proxy/src/auth/backend.rs b/proxy/src/auth/backend.rs
index 04fe83d8eb..e421798067 100644
--- a/proxy/src/auth/backend.rs
+++ b/proxy/src/auth/backend.rs
@@ -12,6 +12,8 @@ use crate::console::errors::GetAuthInfoError;
 use crate::console::provider::{CachedRoleSecret, ConsoleBackend};
 use crate::console::{AuthSecret, NodeInfo};
 use crate::context::RequestMonitoring;
+use crate::intern::EndpointIdInt;
+use crate::metrics::{AUTH_RATE_LIMIT_HITS, ENDPOINTS_AUTH_RATE_LIMITED};
 use crate::proxy::connect_compute::ComputeConnectBackend;
 use crate::proxy::NeonOptions;
 use crate::stream::Stream;
@@ -28,7 +30,7 @@ use crate::{
 use crate::{scram, EndpointCacheKey, EndpointId, RoleName};
 use std::sync::Arc;
 use tokio::io::{AsyncRead, AsyncWrite};
-use tracing::info;
+use tracing::{info, warn};
 
 /// Alternative to [`std::borrow::Cow`] but doesn't need `T: ToOwned` as we don't need that functionality
 pub enum MaybeOwned<'a, T> {
@@ -174,6 +176,52 @@ impl TryFrom<ComputeUserInfoMaybeEndpoint> for ComputeUserInfo {
     }
 }
 
+impl AuthenticationConfig {
+    pub fn check_rate_limit(
+        &self,
+
+        ctx: &mut RequestMonitoring,
+        secret: AuthSecret,
+        endpoint: &EndpointId,
+        is_cleartext: bool,
+    ) -> auth::Result<AuthSecret> {
+        // we have validated the endpoint exists, so let's intern it.
+        let endpoint_int = EndpointIdInt::from(endpoint);
+
+        // only count the full hash count if password hack or websocket flow.
+        // in other words, if proxy needs to run the hashing
+        let password_weight = if is_cleartext {
+            match &secret {
+                #[cfg(any(test, feature = "testing"))]
+                AuthSecret::Md5(_) => 1,
+                AuthSecret::Scram(s) => s.iterations + 1,
+            }
+        } else {
+            // validating scram takes just 1 hmac_sha_256 operation.
+            1
+        };
+
+        let limit_not_exceeded = self
+            .rate_limiter
+            .check((endpoint_int, ctx.peer_addr), password_weight);
+
+        if !limit_not_exceeded {
+            warn!(
+                enabled = self.rate_limiter_enabled,
+                "rate limiting authentication"
+            );
+            AUTH_RATE_LIMIT_HITS.inc();
+            ENDPOINTS_AUTH_RATE_LIMITED.measure(endpoint);
+
+            if self.rate_limiter_enabled {
+                return Err(auth::AuthError::too_many_connections());
+            }
+        }
+
+        Ok(secret)
+    }
+}
+
 /// True to its name, this function encapsulates our current auth trade-offs.
 /// Here, we choose the appropriate auth flow based on circumstances.
 ///
@@ -214,14 +262,24 @@ async fn auth_quirks(
         Some(secret) => secret,
         None => api.get_role_secret(ctx, &info).await?,
     };
+    let (cached_entry, secret) = cached_secret.take_value();
+
+    let secret = match secret {
+        Some(secret) => config.check_rate_limit(
+            ctx,
+            secret,
+            &info.endpoint,
+            unauthenticated_password.is_some() || allow_cleartext,
+        )?,
+        None => {
+            // If we don't have an authentication secret, we mock one to
+            // prevent malicious probing (possible due to missing protocol steps).
+            // This mocked secret will never lead to successful authentication.
+            info!("authentication info not found, mocking it");
+            AuthSecret::Scram(scram::ServerSecret::mock(rand::random()))
+        }
+    };
 
-    let secret = cached_secret.value.clone().unwrap_or_else(|| {
-        // If we don't have an authentication secret, we mock one to
-        // prevent malicious probing (possible due to missing protocol steps).
-        // This mocked secret will never lead to successful authentication.
-        info!("authentication info not found, mocking it");
-        AuthSecret::Scram(scram::ServerSecret::mock(&info.user, rand::random()))
-    });
     match authenticate_with_secret(
         ctx,
         secret,
@@ -237,7 +295,7 @@ async fn auth_quirks(
         Err(e) => {
             if e.is_auth_failed() {
                 // The password could have been changed, so we invalidate the cache.
-                cached_secret.invalidate();
+                cached_entry.invalidate();
             }
             Err(e)
         }
@@ -415,6 +473,7 @@ mod tests {
 
     use bytes::BytesMut;
     use fallible_iterator::FallibleIterator;
+    use once_cell::sync::Lazy;
     use postgres_protocol::{
         authentication::sasl::{ChannelBinding, ScramSha256},
         message::{backend::Message as PgMessage, frontend},
@@ -432,6 +491,7 @@ mod tests {
         },
         context::RequestMonitoring,
         proxy::NeonOptions,
+        rate_limiter::{AuthRateLimiter, RateBucketInfo},
         scram::ServerSecret,
         stream::{PqStream, Stream},
     };
@@ -473,9 +533,11 @@ mod tests {
         }
     }
 
-    static CONFIG: &AuthenticationConfig = &AuthenticationConfig {
+    static CONFIG: Lazy<AuthenticationConfig> = Lazy::new(|| AuthenticationConfig {
         scram_protocol_timeout: std::time::Duration::from_secs(5),
-    };
+        rate_limiter_enabled: true,
+        rate_limiter: AuthRateLimiter::new(&RateBucketInfo::DEFAULT_AUTH_SET),
+    });
 
     async fn read_message(r: &mut (impl AsyncRead + Unpin), b: &mut BytesMut) -> PgMessage {
         loop {
@@ -544,7 +606,7 @@ mod tests {
             }
         });
 
-        let _creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, false, CONFIG)
+        let _creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, false, &CONFIG)
             .await
             .unwrap();
 
@@ -584,7 +646,7 @@ mod tests {
             client.write_all(&write).await.unwrap();
         });
 
-        let _creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, true, CONFIG)
+        let _creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, true, &CONFIG)
             .await
             .unwrap();
 
@@ -624,7 +686,7 @@ mod tests {
             client.write_all(&write).await.unwrap();
         });
 
-        let creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, true, CONFIG)
+        let creds = auth_quirks(&mut ctx, &api, user_info, &mut stream, true, &CONFIG)
             .await
             .unwrap();
 
diff --git a/proxy/src/bin/proxy.rs b/proxy/src/bin/proxy.rs
index d38439c2a0..88b847f5f1 100644
--- a/proxy/src/bin/proxy.rs
+++ b/proxy/src/bin/proxy.rs
@@ -18,6 +18,7 @@ use proxy::console;
 use proxy::context::parquet::ParquetUploadArgs;
 use proxy::http;
 use proxy::metrics::NUM_CANCELLATION_REQUESTS_SOURCE_FROM_CLIENT;
+use proxy::rate_limiter::AuthRateLimiter;
 use proxy::rate_limiter::EndpointRateLimiter;
 use proxy::rate_limiter::RateBucketInfo;
 use proxy::rate_limiter::RateLimiterConfig;
@@ -141,10 +142,16 @@ struct ProxyCliArgs {
     ///
     /// Provided in the form '<Requests Per Second>@<Bucket Duration Size>'.
     /// Can be given multiple times for different bucket sizes.
-    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_SET)]
+    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_ENDPOINT_SET)]
     endpoint_rps_limit: Vec<RateBucketInfo>,
+    /// Whether the auth rate limiter actually takes effect (for testing)
+    #[clap(long, default_value_t = false, value_parser = clap::builder::BoolishValueParser::new(), action = clap::ArgAction::Set)]
+    auth_rate_limit_enabled: bool,
+    /// Authentication rate limiter max number of hashes per second.
+    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_AUTH_SET)]
+    auth_rate_limit: Vec<RateBucketInfo>,
     /// Redis rate limiter max number of requests per second.
-    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_SET)]
+    #[clap(long, default_values_t = RateBucketInfo::DEFAULT_ENDPOINT_SET)]
     redis_rps_limit: Vec<RateBucketInfo>,
     /// Initial limit for dynamic rate limiter. Makes sense only if `rate_limit_algorithm` is *not* `None`.
     #[clap(long, default_value_t = 100)]
@@ -510,6 +517,8 @@ fn build_config(args: &ProxyCliArgs) -> anyhow::Result<&'static ProxyConfig> {
     };
     let authentication_config = AuthenticationConfig {
         scram_protocol_timeout: args.scram_protocol_timeout,
+        rate_limiter_enabled: args.auth_rate_limit_enabled,
+        rate_limiter: AuthRateLimiter::new(args.auth_rate_limit.clone()),
     };
 
     let mut endpoint_rps_limit = args.endpoint_rps_limit.clone();
diff --git a/proxy/src/cache/common.rs b/proxy/src/cache/common.rs
index 2af6a70e90..bc1c37512b 100644
--- a/proxy/src/cache/common.rs
+++ b/proxy/src/cache/common.rs
@@ -43,6 +43,16 @@ impl<C: Cache, V> Cached<C, V> {
         Self { token: None, value }
     }
 
+    pub fn take_value(self) -> (Cached<C, ()>, V) {
+        (
+            Cached {
+                token: self.token,
+                value: (),
+            },
+            self.value,
+        )
+    }
+
     /// Drop this entry from a cache if it's still there.
     pub fn invalidate(self) -> V {
         if let Some((cache, info)) = &self.token {
diff --git a/proxy/src/cache/project_info.rs b/proxy/src/cache/project_info.rs
index 6e3eb8c1b0..5a3660520b 100644
--- a/proxy/src/cache/project_info.rs
+++ b/proxy/src/cache/project_info.rs
@@ -373,10 +373,7 @@ mod tests {
         let endpoint_id = "endpoint".into();
         let user1: RoleName = "user1".into();
         let user2: RoleName = "user2".into();
-        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user1.as_str(),
-            [1; 32],
-        )));
+        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock([1; 32])));
         let secret2 = None;
         let allowed_ips = Arc::new(vec![
             "127.0.0.1".parse().unwrap(),
@@ -395,10 +392,7 @@ mod tests {
 
         // Shouldn't add more than 2 roles.
         let user3: RoleName = "user3".into();
-        let secret3 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user3.as_str(),
-            [3; 32],
-        )));
+        let secret3 = Some(AuthSecret::Scram(ServerSecret::mock([3; 32])));
         cache.insert_role_secret(&project_id, &endpoint_id, &user3, secret3.clone());
         assert!(cache.get_role_secret(&endpoint_id, &user3).is_none());
 
@@ -431,14 +425,8 @@ mod tests {
         let endpoint_id = "endpoint".into();
         let user1: RoleName = "user1".into();
         let user2: RoleName = "user2".into();
-        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user1.as_str(),
-            [1; 32],
-        )));
-        let secret2 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user2.as_str(),
-            [2; 32],
-        )));
+        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock([1; 32])));
+        let secret2 = Some(AuthSecret::Scram(ServerSecret::mock([2; 32])));
         let allowed_ips = Arc::new(vec![
             "127.0.0.1".parse().unwrap(),
             "127.0.0.2".parse().unwrap(),
@@ -486,14 +474,8 @@ mod tests {
         let endpoint_id = "endpoint".into();
         let user1: RoleName = "user1".into();
         let user2: RoleName = "user2".into();
-        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user1.as_str(),
-            [1; 32],
-        )));
-        let secret2 = Some(AuthSecret::Scram(ServerSecret::mock(
-            user2.as_str(),
-            [2; 32],
-        )));
+        let secret1 = Some(AuthSecret::Scram(ServerSecret::mock([1; 32])));
+        let secret2 = Some(AuthSecret::Scram(ServerSecret::mock([2; 32])));
         let allowed_ips = Arc::new(vec![
             "127.0.0.1".parse().unwrap(),
             "127.0.0.2".parse().unwrap(),
diff --git a/proxy/src/config.rs b/proxy/src/config.rs
index 45f8d76144..361c3ef519 100644
--- a/proxy/src/config.rs
+++ b/proxy/src/config.rs
@@ -1,4 +1,8 @@
-use crate::{auth, rate_limiter::RateBucketInfo, serverless::GlobalConnPoolOptions};
+use crate::{
+    auth,
+    rate_limiter::{AuthRateLimiter, RateBucketInfo},
+    serverless::GlobalConnPoolOptions,
+};
 use anyhow::{bail, ensure, Context, Ok};
 use itertools::Itertools;
 use rustls::{
@@ -50,6 +54,8 @@ pub struct HttpConfig {
 
 pub struct AuthenticationConfig {
     pub scram_protocol_timeout: tokio::time::Duration,
+    pub rate_limiter_enabled: bool,
+    pub rate_limiter: AuthRateLimiter,
 }
 
 impl TlsConfig {
diff --git a/proxy/src/metrics.rs b/proxy/src/metrics.rs
index eed45e421b..4172dc19da 100644
--- a/proxy/src/metrics.rs
+++ b/proxy/src/metrics.rs
@@ -4,7 +4,10 @@ use ::metrics::{
     register_int_gauge_vec, Histogram, HistogramVec, HyperLogLogVec, IntCounterPairVec,
     IntCounterVec, IntGauge, IntGaugeVec,
 };
-use metrics::{register_int_counter, register_int_counter_pair, IntCounter, IntCounterPair};
+use metrics::{
+    register_hll, register_int_counter, register_int_counter_pair, HyperLogLog, IntCounter,
+    IntCounterPair,
+};
 
 use once_cell::sync::Lazy;
 use tokio::time::{self, Instant};
@@ -358,3 +361,20 @@ pub static TLS_HANDSHAKE_FAILURES: Lazy<IntCounter> = Lazy::new(|| {
     )
     .unwrap()
 });
+
+pub static ENDPOINTS_AUTH_RATE_LIMITED: Lazy<HyperLogLog<32>> = Lazy::new(|| {
+    register_hll!(
+        32,
+        "proxy_endpoints_auth_rate_limits",
+        "Number of endpoints affected by authentication rate limits",
+    )
+    .unwrap()
+});
+
+pub static AUTH_RATE_LIMIT_HITS: Lazy<IntCounter> = Lazy::new(|| {
+    register_int_counter!(
+        "proxy_requests_auth_rate_limits_total",
+        "Number of connection requests affected by authentication rate limits",
+    )
+    .unwrap()
+});
diff --git a/proxy/src/proxy.rs b/proxy/src/proxy.rs
index 843bfc08cf..6051c0a812 100644
--- a/proxy/src/proxy.rs
+++ b/proxy/src/proxy.rs
@@ -280,7 +280,7 @@ pub async fn handle_client<S: AsyncRead + AsyncWrite + Unpin>(
 
     // check rate limit
     if let Some(ep) = user_info.get_endpoint() {
-        if !endpoint_rate_limiter.check(ep) {
+        if !endpoint_rate_limiter.check(ep, 1) {
             return stream
                 .throw_error(auth::AuthError::too_many_connections())
                 .await?;
diff --git a/proxy/src/proxy/tests.rs b/proxy/src/proxy/tests.rs
index 9c3be73612..a4051447c1 100644
--- a/proxy/src/proxy/tests.rs
+++ b/proxy/src/proxy/tests.rs
@@ -142,8 +142,8 @@ impl Scram {
         Ok(Scram(secret))
     }
 
-    fn mock(user: &str) -> Self {
-        Scram(scram::ServerSecret::mock(user, rand::random()))
+    fn mock() -> Self {
+        Scram(scram::ServerSecret::mock(rand::random()))
     }
 }
 
@@ -330,11 +330,7 @@ async fn scram_auth_mock() -> anyhow::Result<()> {
 
     let (client_config, server_config) =
         generate_tls_config("generic-project-name.localhost", "localhost")?;
-    let proxy = tokio::spawn(dummy_proxy(
-        client,
-        Some(server_config),
-        Scram::mock("user"),
-    ));
+    let proxy = tokio::spawn(dummy_proxy(client, Some(server_config), Scram::mock()));
 
     use rand::{distributions::Alphanumeric, Rng};
     let password: String = rand::thread_rng()
diff --git a/proxy/src/rate_limiter.rs b/proxy/src/rate_limiter.rs
index f0da4ead23..13dffffca0 100644
--- a/proxy/src/rate_limiter.rs
+++ b/proxy/src/rate_limiter.rs
@@ -4,4 +4,4 @@ mod limiter;
 pub use aimd::Aimd;
 pub use limit_algorithm::{AimdConfig, Fixed, RateLimitAlgorithm, RateLimiterConfig};
 pub use limiter::Limiter;
-pub use limiter::{EndpointRateLimiter, RateBucketInfo, RedisRateLimiter};
+pub use limiter::{AuthRateLimiter, EndpointRateLimiter, RateBucketInfo, RedisRateLimiter};
diff --git a/proxy/src/rate_limiter/limiter.rs b/proxy/src/rate_limiter/limiter.rs
index 3181060e2f..f590896dd9 100644
--- a/proxy/src/rate_limiter/limiter.rs
+++ b/proxy/src/rate_limiter/limiter.rs
@@ -1,6 +1,8 @@
 use std::{
+    borrow::Cow,
     collections::hash_map::RandomState,
-    hash::BuildHasher,
+    hash::{BuildHasher, Hash},
+    net::IpAddr,
     sync::{
         atomic::{AtomicUsize, Ordering},
         Arc, Mutex,
@@ -15,7 +17,7 @@ use tokio::sync::{Mutex as AsyncMutex, Semaphore, SemaphorePermit};
 use tokio::time::{timeout, Duration, Instant};
 use tracing::info;
 
-use crate::EndpointId;
+use crate::{intern::EndpointIdInt, EndpointId};
 
 use super::{
     limit_algorithm::{LimitAlgorithm, Sample},
@@ -49,11 +51,11 @@ impl RedisRateLimiter {
             .data
             .iter_mut()
             .zip(self.info)
-            .all(|(bucket, info)| bucket.should_allow_request(info, now));
+            .all(|(bucket, info)| bucket.should_allow_request(info, now, 1));
 
         if should_allow_request {
             // only increment the bucket counts if the request will actually be accepted
-            self.data.iter_mut().for_each(RateBucket::inc);
+            self.data.iter_mut().for_each(|b| b.inc(1));
         }
 
         should_allow_request
@@ -71,9 +73,14 @@ impl RedisRateLimiter {
 // saw SNI, before doing TLS handshake. User-side error messages in that case
 // does not look very nice (`SSL SYSCALL error: Undefined error: 0`), so for now
 // I went with a more expensive way that yields user-friendlier error messages.
-pub struct EndpointRateLimiter<Rand = StdRng, Hasher = RandomState> {
-    map: DashMap<EndpointId, Vec<RateBucket>, Hasher>,
-    info: &'static [RateBucketInfo],
+pub type EndpointRateLimiter = BucketRateLimiter<EndpointId, StdRng, RandomState>;
+
+// This can't be just per IP because that would limit some PaaS that share IP addresses
+pub type AuthRateLimiter = BucketRateLimiter<(EndpointIdInt, IpAddr), StdRng, RandomState>;
+
+pub struct BucketRateLimiter<Key, Rand = StdRng, Hasher = RandomState> {
+    map: DashMap<Key, Vec<RateBucket>, Hasher>,
+    info: Cow<'static, [RateBucketInfo]>,
     access_count: AtomicUsize,
     rand: Mutex<Rand>,
 }
@@ -85,9 +92,9 @@ struct RateBucket {
 }
 
 impl RateBucket {
-    fn should_allow_request(&mut self, info: &RateBucketInfo, now: Instant) -> bool {
+    fn should_allow_request(&mut self, info: &RateBucketInfo, now: Instant, n: u32) -> bool {
         if now - self.start < info.interval {
-            self.count < info.max_rpi
+            self.count + n <= info.max_rpi
         } else {
             // bucket expired, reset
             self.count = 0;
@@ -97,8 +104,8 @@ impl RateBucket {
         }
     }
 
-    fn inc(&mut self) {
-        self.count += 1;
+    fn inc(&mut self, n: u32) {
+        self.count += n;
     }
 }
 
@@ -111,7 +118,7 @@ pub struct RateBucketInfo {
 
 impl std::fmt::Display for RateBucketInfo {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        let rps = self.max_rpi * 1000 / self.interval.as_millis() as u32;
+        let rps = (self.max_rpi as u64) * 1000 / self.interval.as_millis() as u64;
         write!(f, "{rps}@{}", humantime::format_duration(self.interval))
     }
 }
@@ -136,12 +143,25 @@ impl std::str::FromStr for RateBucketInfo {
 }
 
 impl RateBucketInfo {
-    pub const DEFAULT_SET: [Self; 3] = [
+    pub const DEFAULT_ENDPOINT_SET: [Self; 3] = [
         Self::new(300, Duration::from_secs(1)),
         Self::new(200, Duration::from_secs(60)),
         Self::new(100, Duration::from_secs(600)),
     ];
 
+    /// All of these are per endpoint-ip pair.
+    /// Context: 4096 rounds of pbkdf2 take about 1ms of cpu time to execute (1 milli-cpu-second or 1mcpus).
+    ///
+    /// First bucket: 300mcpus total per endpoint-ip pair
+    /// * 1228800 requests per second with 1 hash rounds. (endpoint rate limiter will catch this first)
+    /// * 300 requests per second with 4096 hash rounds.
+    /// * 2 requests per second with 600000 hash rounds.
+    pub const DEFAULT_AUTH_SET: [Self; 3] = [
+        Self::new(300 * 4096, Duration::from_secs(1)),
+        Self::new(200 * 4096, Duration::from_secs(60)),
+        Self::new(100 * 4096, Duration::from_secs(600)),
+    ];
+
     pub fn validate(info: &mut [Self]) -> anyhow::Result<()> {
         info.sort_unstable_by_key(|info| info.interval);
         let invalid = info
@@ -150,7 +170,7 @@ impl RateBucketInfo {
             .find(|(a, b)| a.max_rpi > b.max_rpi);
         if let Some((a, b)) = invalid {
             bail!(
-                "invalid endpoint RPS limits. {b} allows fewer requests per bucket than {a} ({} vs {})",
+                "invalid bucket RPS limits. {b} allows fewer requests per bucket than {a} ({} vs {})",
                 b.max_rpi,
                 a.max_rpi,
             );
@@ -162,19 +182,24 @@ impl RateBucketInfo {
     pub const fn new(max_rps: u32, interval: Duration) -> Self {
         Self {
             interval,
-            max_rpi: max_rps * interval.as_millis() as u32 / 1000,
+            max_rpi: ((max_rps as u64) * (interval.as_millis() as u64) / 1000) as u32,
         }
     }
 }
 
-impl EndpointRateLimiter {
-    pub fn new(info: &'static [RateBucketInfo]) -> Self {
+impl<K: Hash + Eq> BucketRateLimiter<K> {
+    pub fn new(info: impl Into<Cow<'static, [RateBucketInfo]>>) -> Self {
         Self::new_with_rand_and_hasher(info, StdRng::from_entropy(), RandomState::new())
     }
 }
 
-impl<R: Rng, S: BuildHasher + Clone> EndpointRateLimiter<R, S> {
-    fn new_with_rand_and_hasher(info: &'static [RateBucketInfo], rand: R, hasher: S) -> Self {
+impl<K: Hash + Eq, R: Rng, S: BuildHasher + Clone> BucketRateLimiter<K, R, S> {
+    fn new_with_rand_and_hasher(
+        info: impl Into<Cow<'static, [RateBucketInfo]>>,
+        rand: R,
+        hasher: S,
+    ) -> Self {
+        let info = info.into();
         info!(buckets = ?info, "endpoint rate limiter");
         Self {
             info,
@@ -185,7 +210,7 @@ impl<R: Rng, S: BuildHasher + Clone> EndpointRateLimiter<R, S> {
     }
 
     /// Check that number of connections to the endpoint is below `max_rps` rps.
-    pub fn check(&self, endpoint: EndpointId) -> bool {
+    pub fn check(&self, key: K, n: u32) -> bool {
         // do a partial GC every 2k requests. This cleans up ~ 1/64th of the map.
         // worst case memory usage is about:
         //    = 2 * 2048 * 64 * (48B + 72B)
@@ -195,7 +220,7 @@ impl<R: Rng, S: BuildHasher + Clone> EndpointRateLimiter<R, S> {
         }
 
         let now = Instant::now();
-        let mut entry = self.map.entry(endpoint).or_insert_with(|| {
+        let mut entry = self.map.entry(key).or_insert_with(|| {
             vec![
                 RateBucket {
                     start: now,
@@ -207,12 +232,12 @@ impl<R: Rng, S: BuildHasher + Clone> EndpointRateLimiter<R, S> {
 
         let should_allow_request = entry
             .iter_mut()
-            .zip(self.info)
-            .all(|(bucket, info)| bucket.should_allow_request(info, now));
+            .zip(&*self.info)
+            .all(|(bucket, info)| bucket.should_allow_request(info, now, n));
 
         if should_allow_request {
             // only increment the bucket counts if the request will actually be accepted
-            entry.iter_mut().for_each(RateBucket::inc);
+            entry.iter_mut().for_each(|b| b.inc(n));
         }
 
         should_allow_request
@@ -223,7 +248,7 @@ impl<R: Rng, S: BuildHasher + Clone> EndpointRateLimiter<R, S> {
     /// But that way deletion does not aquire mutex on each entry access.
     pub fn do_gc(&self) {
         info!(
-            "cleaning up endpoint rate limiter, current size = {}",
+            "cleaning up bucket rate limiter, current size = {}",
             self.map.len()
         );
         let n = self.map.shards().len();
@@ -534,7 +559,7 @@ mod tests {
     use rustc_hash::FxHasher;
     use tokio::time;
 
-    use super::{EndpointRateLimiter, Limiter, Outcome};
+    use super::{BucketRateLimiter, EndpointRateLimiter, Limiter, Outcome};
     use crate::{
         rate_limiter::{RateBucketInfo, RateLimitAlgorithm},
         EndpointId,
@@ -672,12 +697,12 @@ mod tests {
 
     #[test]
     fn default_rate_buckets() {
-        let mut defaults = RateBucketInfo::DEFAULT_SET;
+        let mut defaults = RateBucketInfo::DEFAULT_ENDPOINT_SET;
         RateBucketInfo::validate(&mut defaults[..]).unwrap();
     }
 
     #[test]
-    #[should_panic = "invalid endpoint RPS limits. 10@10s allows fewer requests per bucket than 300@1s (100 vs 300)"]
+    #[should_panic = "invalid bucket RPS limits. 10@10s allows fewer requests per bucket than 300@1s (100 vs 300)"]
     fn rate_buckets_validate() {
         let mut rates: Vec<RateBucketInfo> = ["300@1s", "10@10s"]
             .into_iter()
@@ -693,42 +718,42 @@ mod tests {
             .map(|s| s.parse().unwrap())
             .collect();
         RateBucketInfo::validate(&mut rates).unwrap();
-        let limiter = EndpointRateLimiter::new(Vec::leak(rates));
+        let limiter = EndpointRateLimiter::new(rates);
 
         let endpoint = EndpointId::from("ep-my-endpoint-1234");
 
         time::pause();
 
         for _ in 0..100 {
-            assert!(limiter.check(endpoint.clone()));
+            assert!(limiter.check(endpoint.clone(), 1));
         }
         // more connections fail
-        assert!(!limiter.check(endpoint.clone()));
+        assert!(!limiter.check(endpoint.clone(), 1));
 
         // fail even after 500ms as it's in the same bucket
         time::advance(time::Duration::from_millis(500)).await;
-        assert!(!limiter.check(endpoint.clone()));
+        assert!(!limiter.check(endpoint.clone(), 1));
 
         // after a full 1s, 100 requests are allowed again
         time::advance(time::Duration::from_millis(500)).await;
         for _ in 1..6 {
-            for _ in 0..100 {
-                assert!(limiter.check(endpoint.clone()));
+            for _ in 0..50 {
+                assert!(limiter.check(endpoint.clone(), 2));
             }
             time::advance(time::Duration::from_millis(1000)).await;
         }
 
         // more connections after 600 will exceed the 20rps@30s limit
-        assert!(!limiter.check(endpoint.clone()));
+        assert!(!limiter.check(endpoint.clone(), 1));
 
         // will still fail before the 30 second limit
         time::advance(time::Duration::from_millis(30_000 - 6_000 - 1)).await;
-        assert!(!limiter.check(endpoint.clone()));
+        assert!(!limiter.check(endpoint.clone(), 1));
 
         // after the full 30 seconds, 100 requests are allowed again
         time::advance(time::Duration::from_millis(1)).await;
         for _ in 0..100 {
-            assert!(limiter.check(endpoint.clone()));
+            assert!(limiter.check(endpoint.clone(), 1));
         }
     }
 
@@ -738,14 +763,41 @@ mod tests {
         let rand = rand::rngs::StdRng::from_seed([1; 32]);
         let hasher = BuildHasherDefault::<FxHasher>::default();
 
-        let limiter = EndpointRateLimiter::new_with_rand_and_hasher(
-            &RateBucketInfo::DEFAULT_SET,
+        let limiter = BucketRateLimiter::new_with_rand_and_hasher(
+            &RateBucketInfo::DEFAULT_ENDPOINT_SET,
             rand,
             hasher,
         );
         for i in 0..1_000_000 {
-            limiter.check(format!("{i}").into());
+            limiter.check(i, 1);
         }
         assert!(limiter.map.len() < 150_000);
     }
+
+    #[test]
+    fn test_default_auth_set() {
+        // these values used to exceed u32::MAX
+        assert_eq!(
+            RateBucketInfo::DEFAULT_AUTH_SET,
+            [
+                RateBucketInfo {
+                    interval: Duration::from_secs(1),
+                    max_rpi: 300 * 4096,
+                },
+                RateBucketInfo {
+                    interval: Duration::from_secs(60),
+                    max_rpi: 200 * 4096 * 60,
+                },
+                RateBucketInfo {
+                    interval: Duration::from_secs(600),
+                    max_rpi: 100 * 4096 * 600,
+                }
+            ]
+        );
+
+        for x in RateBucketInfo::DEFAULT_AUTH_SET {
+            let y = x.to_string().parse().unwrap();
+            assert_eq!(x, y);
+        }
+    }
 }
diff --git a/proxy/src/scram/secret.rs b/proxy/src/scram/secret.rs
index f3414cb8ec..44c4f9e44a 100644
--- a/proxy/src/scram/secret.rs
+++ b/proxy/src/scram/secret.rs
@@ -50,13 +50,13 @@ impl ServerSecret {
     /// To avoid revealing information to an attacker, we use a
     /// mocked server secret even if the user doesn't exist.
     /// See `auth-scram.c : mock_scram_secret` for details.
-    pub fn mock(user: &str, nonce: [u8; 32]) -> Self {
-        // Refer to `auth-scram.c : scram_mock_salt`.
-        let mocked_salt = super::sha256([user.as_bytes(), &nonce]);
-
+    pub fn mock(nonce: [u8; 32]) -> Self {
         Self {
-            iterations: 4096,
-            salt_base64: base64::encode(mocked_salt),
+            // this doesn't reveal much information as we're going to use
+            // iteration count 1 for our generated passwords going forward.
+            // PG16 users can set iteration count=1 already today.
+            iterations: 1,
+            salt_base64: base64::encode(nonce),
             stored_key: ScramKey::default(),
             server_key: ScramKey::default(),
             doomed: true,
diff --git a/proxy/src/serverless/backend.rs b/proxy/src/serverless/backend.rs
index 72b55c45f0..f10779d7ba 100644
--- a/proxy/src/serverless/backend.rs
+++ b/proxy/src/serverless/backend.rs
@@ -42,7 +42,12 @@ impl PoolingBackend {
         };
 
         let secret = match cached_secret.value.clone() {
-            Some(secret) => secret,
+            Some(secret) => self.config.authentication_config.check_rate_limit(
+                ctx,
+                secret,
+                &user_info.endpoint,
+                true,
+            )?,
             None => {
                 // If we don't have an authentication secret, for the http flow we can just return an error.
                 info!("authentication info not found");
diff --git a/test_runner/fixtures/neon_fixtures.py b/test_runner/fixtures/neon_fixtures.py
index f22ce10c20..3d60f9bef5 100644
--- a/test_runner/fixtures/neon_fixtures.py
+++ b/test_runner/fixtures/neon_fixtures.py
@@ -2126,6 +2126,8 @@ class NeonStorageController(MetricsGetter):
             shard_params = {"count": shard_count}
             if shard_stripe_size is not None:
                 shard_params["stripe_size"] = shard_stripe_size
+            else:
+                shard_params["stripe_size"] = 32768
 
             body["shard_parameters"] = shard_params
 
@@ -2139,6 +2141,7 @@ class NeonStorageController(MetricsGetter):
             json=body,
             headers=self.headers(TokenScope.PAGE_SERVER_API),
         )
+        response.raise_for_status()
         log.info(f"tenant_create success: {response.json()}")
 
     def locate(self, tenant_id: TenantId) -> list[dict[str, Any]]:
diff --git a/test_runner/fixtures/pageserver/allowed_errors.py b/test_runner/fixtures/pageserver/allowed_errors.py
index d7f682dad3..8b895dcd92 100755
--- a/test_runner/fixtures/pageserver/allowed_errors.py
+++ b/test_runner/fixtures/pageserver/allowed_errors.py
@@ -86,6 +86,9 @@ DEFAULT_PAGESERVER_ALLOWED_ERRORS = (
     # This is especially pronounced in tests that set small checkpoint
     # distances.
     ".*Flushed oversized open layer with size.*",
+    # During teardown, we stop the storage controller before the pageservers, so pageservers
+    # can experience connection errors doing background deletion queue work.
+    ".*WARN deletion backend: calling control plane generation validation API failed.*Connection refused.*",
 )
 
 
diff --git a/test_runner/performance/test_bulk_insert.py b/test_runner/performance/test_bulk_insert.py
index 9e3f602237..1df3f2f5f1 100644
--- a/test_runner/performance/test_bulk_insert.py
+++ b/test_runner/performance/test_bulk_insert.py
@@ -1,5 +1,6 @@
 from contextlib import closing
 
+import pytest
 from fixtures.benchmark_fixture import MetricReport
 from fixtures.compare_fixtures import NeonCompare, PgCompare
 from fixtures.pageserver.utils import wait_tenant_status_404
@@ -17,6 +18,7 @@ from fixtures.types import Lsn
 # 3. Disk space used
 # 4. Peak memory usage
 #
+@pytest.mark.skip("See https://github.com/neondatabase/neon/issues/7124")
 def test_bulk_insert(neon_with_baseline: PgCompare):
     env = neon_with_baseline
 
diff --git a/test_runner/regress/test_pageserver_layer_rolling.py b/test_runner/regress/test_pageserver_layer_rolling.py
new file mode 100644
index 0000000000..c7e1e88468
--- /dev/null
+++ b/test_runner/regress/test_pageserver_layer_rolling.py
@@ -0,0 +1,275 @@
+import asyncio
+import os
+from typing import Tuple
+
+import psutil
+import pytest
+from fixtures.log_helper import log
+from fixtures.neon_fixtures import (
+    NeonEnv,
+    NeonEnvBuilder,
+    tenant_get_shards,
+)
+from fixtures.pageserver.http import PageserverHttpClient
+from fixtures.pageserver.utils import wait_for_last_record_lsn, wait_for_upload
+from fixtures.types import Lsn, TenantId, TimelineId
+from fixtures.utils import wait_until
+
+TIMELINE_COUNT = 10
+ENTRIES_PER_TIMELINE = 10_000
+CHECKPOINT_TIMEOUT_SECONDS = 60
+
+
+async def run_worker(env: NeonEnv, tenant_conf, entries: int) -> Tuple[TenantId, TimelineId, Lsn]:
+    tenant, timeline = env.neon_cli.create_tenant(conf=tenant_conf)
+    with env.endpoints.create_start("main", tenant_id=tenant) as ep:
+        conn = await ep.connect_async()
+        try:
+            await conn.execute("CREATE TABLE IF NOT EXISTS t(key serial primary key, value text)")
+            await conn.execute(
+                f"INSERT INTO t SELECT i, CONCAT('payload_', i) FROM generate_series(0,{entries}) as i"
+            )
+        finally:
+            await conn.close(timeout=10)
+
+        last_flush_lsn = Lsn(ep.safe_psql("SELECT pg_current_wal_flush_lsn()")[0][0])
+        return tenant, timeline, last_flush_lsn
+
+
+async def workload(
+    env: NeonEnv, tenant_conf, timelines: int, entries: int
+) -> list[Tuple[TenantId, TimelineId, Lsn]]:
+    workers = [asyncio.create_task(run_worker(env, tenant_conf, entries)) for _ in range(timelines)]
+    return await asyncio.gather(*workers)
+
+
+def wait_until_pageserver_is_caught_up(
+    env: NeonEnv, last_flush_lsns: list[Tuple[TenantId, TimelineId, Lsn]]
+):
+    for tenant, timeline, last_flush_lsn in last_flush_lsns:
+        shards = tenant_get_shards(env, tenant)
+        for tenant_shard_id, pageserver in shards:
+            waited = wait_for_last_record_lsn(
+                pageserver.http_client(), tenant_shard_id, timeline, last_flush_lsn
+            )
+            assert waited >= last_flush_lsn
+
+
+def wait_until_pageserver_has_uploaded(
+    env: NeonEnv, last_flush_lsns: list[Tuple[TenantId, TimelineId, Lsn]]
+):
+    for tenant, timeline, last_flush_lsn in last_flush_lsns:
+        shards = tenant_get_shards(env, tenant)
+        for tenant_shard_id, pageserver in shards:
+            wait_for_upload(pageserver.http_client(), tenant_shard_id, timeline, last_flush_lsn)
+
+
+def wait_for_wal_ingest_metric(pageserver_http: PageserverHttpClient) -> float:
+    def query():
+        value = pageserver_http.get_metric_value("pageserver_wal_ingest_records_received_total")
+        assert value is not None
+        return value
+
+    # The metric gets initialised on the first update.
+    # Retry a few times, but return 0 if it's stable.
+    try:
+        return float(wait_until(3, 0.5, query))
+    except Exception:
+        return 0
+
+
+def get_dirty_bytes(env):
+    v = env.pageserver.http_client().get_metric_value("pageserver_timeline_ephemeral_bytes") or 0
+    log.info(f"dirty_bytes: {v}")
+    return v
+
+
+def assert_dirty_bytes(env, v):
+    assert get_dirty_bytes(env) == v
+
+
+def assert_dirty_bytes_nonzero(env):
+    assert get_dirty_bytes(env) > 0
+
+
+@pytest.mark.parametrize("immediate_shutdown", [True, False])
+def test_pageserver_small_inmemory_layers(
+    neon_env_builder: NeonEnvBuilder, immediate_shutdown: bool
+):
+    """
+    Test that open layers get flushed after the `checkpoint_timeout` config
+    and do not require WAL reingest upon restart.
+
+    The workload creates a number of timelines and writes some data to each,
+    but not enough to trigger flushes via the `checkpoint_distance` config.
+    """
+    tenant_conf = {
+        # Large `checkpoint_distance` effectively disables size
+        # based checkpointing.
+        "checkpoint_distance": f"{2 * 1024 ** 3}",
+        "checkpoint_timeout": f"{CHECKPOINT_TIMEOUT_SECONDS}s",
+        "compaction_period": "1s",
+    }
+
+    env = neon_env_builder.init_configs()
+    env.start()
+
+    last_flush_lsns = asyncio.run(workload(env, tenant_conf, TIMELINE_COUNT, ENTRIES_PER_TIMELINE))
+    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
+
+    # We didn't write enough data to trigger a size-based checkpoint: we should see dirty data.
+    wait_until(10, 1, lambda: assert_dirty_bytes_nonzero(env))  # type: ignore
+
+    ps_http_client = env.pageserver.http_client()
+    total_wal_ingested_before_restart = wait_for_wal_ingest_metric(ps_http_client)
+
+    # Within ~ the checkpoint interval, all the ephemeral layers should be frozen and flushed,
+    # such that there are zero bytes of ephemeral layer left on the pageserver
+    log.info("Waiting for background checkpoints...")
+    wait_until(CHECKPOINT_TIMEOUT_SECONDS * 2, 1, lambda: assert_dirty_bytes(env, 0))  # type: ignore
+
+    # Zero ephemeral layer bytes does not imply that all the frozen layers were uploaded: they
+    # must be uploaded to remain visible to the pageserver after restart.
+    wait_until_pageserver_has_uploaded(env, last_flush_lsns)
+
+    env.pageserver.restart(immediate=immediate_shutdown)
+    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
+
+    # Catching up with WAL ingest should have resulted in zero bytes of ephemeral layers, since
+    # we froze, flushed and uploaded everything before restarting.  There can be no more WAL writes
+    # because we shut down compute endpoints before flushing.
+    assert get_dirty_bytes(env) == 0
+
+    total_wal_ingested_after_restart = wait_for_wal_ingest_metric(ps_http_client)
+
+    log.info(f"WAL ingested before restart: {total_wal_ingested_before_restart}")
+    log.info(f"WAL ingested after restart: {total_wal_ingested_after_restart}")
+
+    assert total_wal_ingested_after_restart == 0
+
+
+def test_idle_checkpoints(neon_env_builder: NeonEnvBuilder):
+    """
+    Test that `checkpoint_timeout` is enforced even if there is no safekeeper input.
+    """
+    tenant_conf = {
+        # Large `checkpoint_distance` effectively disables size
+        # based checkpointing.
+        "checkpoint_distance": f"{2 * 1024 ** 3}",
+        "checkpoint_timeout": f"{CHECKPOINT_TIMEOUT_SECONDS}s",
+        "compaction_period": "1s",
+    }
+
+    env = neon_env_builder.init_configs()
+    env.start()
+
+    last_flush_lsns = asyncio.run(workload(env, tenant_conf, TIMELINE_COUNT, ENTRIES_PER_TIMELINE))
+    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
+
+    # We didn't write enough data to trigger a size-based checkpoint: we should see dirty data.
+    wait_until(10, 1, lambda: assert_dirty_bytes_nonzero(env))  # type: ignore
+
+    # Stop the safekeepers, so that we cannot have any more WAL receiver connections
+    for sk in env.safekeepers:
+        sk.stop()
+
+    # We should have got here fast enough that we didn't hit the background interval yet,
+    # and the teardown of SK connections shouldn't prompt any layer freezing.
+    assert get_dirty_bytes(env) > 0
+
+    # Within ~ the checkpoint interval, all the ephemeral layers should be frozen and flushed,
+    # such that there are zero bytes of ephemeral layer left on the pageserver
+    log.info("Waiting for background checkpoints...")
+    wait_until(CHECKPOINT_TIMEOUT_SECONDS * 2, 1, lambda: assert_dirty_bytes(env, 0))  # type: ignore
+
+
+@pytest.mark.skipif(
+    # We have to use at least ~100MB of data to hit the lowest limit we can configure, which is
+    # prohibitively slow in debug mode
+    os.getenv("BUILD_TYPE") == "debug",
+    reason="Avoid running bulkier ingest tests in debug mode",
+)
+def test_total_size_limit(neon_env_builder: NeonEnvBuilder):
+    """
+    Test that checkpoints are done based on total ephemeral layer size, even if no one timeline is
+    individually exceeding checkpoint thresholds.
+    """
+
+    system_memory = psutil.virtual_memory().total
+
+    # The smallest total size limit we can configure is 1/1024th of the system memory (e.g. 128MB on
+    # a system with 128GB of RAM).  We will then write enough data to violate this limit.
+    max_dirty_data = 128 * 1024 * 1024
+    ephemeral_bytes_per_memory_kb = (max_dirty_data * 1024) // system_memory
+    assert ephemeral_bytes_per_memory_kb > 0
+
+    neon_env_builder.pageserver_config_override = f"""
+        ephemeral_bytes_per_memory_kb={ephemeral_bytes_per_memory_kb}
+        """
+
+    compaction_period_s = 10
+
+    tenant_conf = {
+        # Large space + time thresholds: effectively disable these limits
+        "checkpoint_distance": f"{1024 ** 4}",
+        "checkpoint_timeout": "3600s",
+        "compaction_period": f"{compaction_period_s}s",
+    }
+
+    env = neon_env_builder.init_configs()
+    env.start()
+
+    timeline_count = 10
+
+    # This is about 2MiB of data per timeline
+    entries_per_timeline = 100_000
+
+    last_flush_lsns = asyncio.run(workload(env, tenant_conf, timeline_count, entries_per_timeline))
+    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
+
+    total_bytes_ingested = 0
+    for tenant, timeline, last_flush_lsn in last_flush_lsns:
+        http_client = env.pageserver.http_client()
+        initdb_lsn = Lsn(http_client.timeline_detail(tenant, timeline)["initdb_lsn"])
+        total_bytes_ingested += last_flush_lsn - initdb_lsn
+
+    log.info(f"Ingested {total_bytes_ingested} bytes since initdb (vs max dirty {max_dirty_data})")
+    assert total_bytes_ingested > max_dirty_data
+
+    # Expected end state: the total physical size of all the tenants is in excess of the max dirty
+    # data, but the total amount of dirty data is less than the limit: this demonstrates that we
+    # have exceeded the threshold but then rolled layers in response
+    def get_total_historic_layers():
+        total_ephemeral_layers = 0
+        total_historic_bytes = 0
+        for tenant, timeline, _last_flush_lsn in last_flush_lsns:
+            http_client = env.pageserver.http_client()
+            initdb_lsn = Lsn(http_client.timeline_detail(tenant, timeline)["initdb_lsn"])
+            layer_map = http_client.layer_map_info(tenant, timeline)
+            total_historic_bytes += sum(
+                layer.layer_file_size
+                for layer in layer_map.historic_layers
+                if layer.layer_file_size is not None and Lsn(layer.lsn_start) > initdb_lsn
+            )
+            total_ephemeral_layers += len(layer_map.in_memory_layers)
+
+        log.info(
+            f"Total historic layer bytes: {total_historic_bytes} ({total_ephemeral_layers} ephemeral layers)"
+        )
+
+        return total_historic_bytes
+
+    def assert_bytes_rolled():
+        assert total_bytes_ingested - get_total_historic_layers() <= max_dirty_data
+
+    # Wait until enough layers have rolled that the amount of dirty data is under the threshold.
+    # We do this indirectly via layer maps, rather than the dirty bytes metric, to avoid false-passing
+    # if that metric isn't updated quickly enough to reflect the dirty bytes exceeding the limit.
+    wait_until(compaction_period_s * 2, 1, assert_bytes_rolled)
+
+    # The end state should also have the reported metric under the limit
+    def assert_dirty_data_limited():
+        dirty_bytes = get_dirty_bytes(env)
+        assert dirty_bytes < max_dirty_data
+
+    wait_until(compaction_period_s * 2, 1, lambda: assert_dirty_data_limited())  # type: ignore
diff --git a/test_runner/regress/test_pageserver_secondary.py b/test_runner/regress/test_pageserver_secondary.py
index 25510c50e6..ca6f77c75f 100644
--- a/test_runner/regress/test_pageserver_secondary.py
+++ b/test_runner/regress/test_pageserver_secondary.py
@@ -90,6 +90,8 @@ def test_location_conf_churn(neon_env_builder: NeonEnvBuilder, seed: int):
                 # this shutdown case is logged at WARN severity by the time it bubbles up to logical size calculation code
                 # WARN ...: initial size calculation failed: downloading failed, possibly for shutdown
                 ".*downloading failed, possibly for shutdown",
+                # {tenant_id=... timeline_id=...}:handle_pagerequests:handle_get_page_at_lsn_request{rel=1664/0/1260 blkno=0 req_lsn=0/149F0D8}: error reading relation or page version: Not found: will not become active.  Current state: Stopping\n'
+                ".*page_service.*will not become active.*",
             ]
         )
 
diff --git a/test_runner/regress/test_pageserver_small_inmemory_layers.py b/test_runner/regress/test_pageserver_small_inmemory_layers.py
deleted file mode 100644
index 714d1c1229..0000000000
--- a/test_runner/regress/test_pageserver_small_inmemory_layers.py
+++ /dev/null
@@ -1,143 +0,0 @@
-import asyncio
-from typing import Tuple
-
-import pytest
-from fixtures.log_helper import log
-from fixtures.neon_fixtures import (
-    NeonEnv,
-    NeonEnvBuilder,
-    tenant_get_shards,
-)
-from fixtures.pageserver.http import PageserverHttpClient
-from fixtures.pageserver.utils import wait_for_last_record_lsn, wait_for_upload
-from fixtures.types import Lsn, TenantId, TimelineId
-from fixtures.utils import wait_until
-
-TIMELINE_COUNT = 10
-ENTRIES_PER_TIMELINE = 10_000
-CHECKPOINT_TIMEOUT_SECONDS = 60
-
-TENANT_CONF = {
-    # Large `checkpoint_distance` effectively disables size
-    # based checkpointing.
-    "checkpoint_distance": f"{2 * 1024 ** 3}",
-    "checkpoint_timeout": f"{CHECKPOINT_TIMEOUT_SECONDS}s",
-}
-
-
-async def run_worker(env: NeonEnv, entries: int) -> Tuple[TenantId, TimelineId, Lsn]:
-    tenant, timeline = env.neon_cli.create_tenant(conf=TENANT_CONF)
-    with env.endpoints.create_start("main", tenant_id=tenant) as ep:
-        conn = await ep.connect_async()
-        try:
-            await conn.execute("CREATE TABLE IF NOT EXISTS t(key serial primary key, value text)")
-            await conn.execute(
-                f"INSERT INTO t SELECT i, CONCAT('payload_', i) FROM generate_series(0,{entries}) as i"
-            )
-        finally:
-            await conn.close(timeout=10)
-
-        last_flush_lsn = Lsn(ep.safe_psql("SELECT pg_current_wal_flush_lsn()")[0][0])
-        return tenant, timeline, last_flush_lsn
-
-
-async def workload(
-    env: NeonEnv, timelines: int, entries: int
-) -> list[Tuple[TenantId, TimelineId, Lsn]]:
-    workers = [asyncio.create_task(run_worker(env, entries)) for _ in range(timelines)]
-    return await asyncio.gather(*workers)
-
-
-def wait_until_pageserver_is_caught_up(
-    env: NeonEnv, last_flush_lsns: list[Tuple[TenantId, TimelineId, Lsn]]
-):
-    for tenant, timeline, last_flush_lsn in last_flush_lsns:
-        shards = tenant_get_shards(env, tenant)
-        for tenant_shard_id, pageserver in shards:
-            waited = wait_for_last_record_lsn(
-                pageserver.http_client(), tenant_shard_id, timeline, last_flush_lsn
-            )
-            assert waited >= last_flush_lsn
-
-
-def wait_until_pageserver_has_uploaded(
-    env: NeonEnv, last_flush_lsns: list[Tuple[TenantId, TimelineId, Lsn]]
-):
-    for tenant, timeline, last_flush_lsn in last_flush_lsns:
-        shards = tenant_get_shards(env, tenant)
-        for tenant_shard_id, pageserver in shards:
-            wait_for_upload(pageserver.http_client(), tenant_shard_id, timeline, last_flush_lsn)
-
-
-def wait_for_wal_ingest_metric(pageserver_http: PageserverHttpClient) -> float:
-    def query():
-        value = pageserver_http.get_metric_value("pageserver_wal_ingest_records_received_total")
-        assert value is not None
-        return value
-
-    # The metric gets initialised on the first update.
-    # Retry a few times, but return 0 if it's stable.
-    try:
-        return float(wait_until(3, 0.5, query))
-    except Exception:
-        return 0
-
-
-@pytest.mark.parametrize("immediate_shutdown", [True, False])
-def test_pageserver_small_inmemory_layers(
-    neon_env_builder: NeonEnvBuilder, immediate_shutdown: bool
-):
-    """
-    Test that open layers get flushed after the `checkpoint_timeout` config
-    and do not require WAL reingest upon restart.
-
-    The workload creates a number of timelines and writes some data to each,
-    but not enough to trigger flushes via the `checkpoint_distance` config.
-    """
-
-    def get_dirty_bytes():
-        v = (
-            env.pageserver.http_client().get_metric_value("pageserver_timeline_ephemeral_bytes")
-            or 0
-        )
-        log.info(f"dirty_bytes: {v}")
-        return v
-
-    def assert_dirty_bytes(v):
-        assert get_dirty_bytes() == v
-
-    env = neon_env_builder.init_configs()
-    env.start()
-
-    last_flush_lsns = asyncio.run(workload(env, TIMELINE_COUNT, ENTRIES_PER_TIMELINE))
-    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
-
-    # We didn't write enough data to trigger a size-based checkpoint
-    assert get_dirty_bytes() > 0
-
-    ps_http_client = env.pageserver.http_client()
-    total_wal_ingested_before_restart = wait_for_wal_ingest_metric(ps_http_client)
-
-    # Within ~ the checkpoint interval, all the ephemeral layers should be frozen and flushed,
-    # such that there are zero bytes of ephemeral layer left on the pageserver
-    log.info("Waiting for background checkpoints...")
-    wait_until(CHECKPOINT_TIMEOUT_SECONDS * 2, 1, lambda: assert_dirty_bytes(0))  # type: ignore
-
-    # Zero ephemeral layer bytes does not imply that all the frozen layers were uploaded: they
-    # must be uploaded to remain visible to the pageserver after restart.
-    wait_until_pageserver_has_uploaded(env, last_flush_lsns)
-
-    env.pageserver.restart(immediate=immediate_shutdown)
-    wait_until_pageserver_is_caught_up(env, last_flush_lsns)
-
-    # Catching up with WAL ingest should have resulted in zero bytes of ephemeral layers, since
-    # we froze, flushed and uploaded everything before restarting.  There can be no more WAL writes
-    # because we shut down compute endpoints before flushing.
-    assert get_dirty_bytes() == 0
-
-    total_wal_ingested_after_restart = wait_for_wal_ingest_metric(ps_http_client)
-
-    log.info(f"WAL ingested before restart: {total_wal_ingested_before_restart}")
-    log.info(f"WAL ingested after restart: {total_wal_ingested_after_restart}")
-
-    assert total_wal_ingested_after_restart == 0
diff --git a/test_runner/regress/test_sharding_service.py b/test_runner/regress/test_sharding_service.py
index b7488cadd6..fc6c137667 100644
--- a/test_runner/regress/test_sharding_service.py
+++ b/test_runner/regress/test_sharding_service.py
@@ -89,6 +89,11 @@ def test_sharding_service_smoke(
     for tid in tenant_ids:
         env.neon_cli.create_tenant(tid, shard_count=shards_per_tenant)
 
+    # Repeating a creation should be idempotent (we are just testing it doesn't return an error)
+    env.storage_controller.tenant_create(
+        tenant_id=next(iter(tenant_ids)), shard_count=shards_per_tenant
+    )
+
     for node_id, count in get_node_shard_counts(env, tenant_ids).items():
         # we used a multiple of pagservers for the total shard count,
         # so expect equal number on all pageservers
diff --git a/test_runner/regress/test_tenants.py b/test_runner/regress/test_tenants.py
index f8701b65d7..2832304dcc 100644
--- a/test_runner/regress/test_tenants.py
+++ b/test_runner/regress/test_tenants.py
@@ -389,6 +389,9 @@ def test_create_churn_during_restart(neon_env_builder: NeonEnvBuilder):
             if e.status_code == 409:
                 log.info(f"delay_ms={delay_ms} 409")
                 pass
+            elif e.status_code == 429:
+                log.info(f"delay_ms={delay_ms} 429")
+                pass
             elif e.status_code == 400:
                 if "is less than existing" in e.message:
                     # We send creation requests very close together in time: it is expected that these