diff --git a/pageserver/benches/bench_ingest.rs b/pageserver/benches/bench_ingest.rs
index 3108b5351f..5c16548de8 100644
--- a/pageserver/benches/bench_ingest.rs
+++ b/pageserver/benches/bench_ingest.rs
@@ -11,6 +11,7 @@ use pageserver::task_mgr::TaskKind;
 use pageserver::tenant::storage_layer::InMemoryLayer;
 use pageserver::{page_cache, virtual_file};
 use pageserver_api::key::Key;
+use pageserver_api::models::virtual_file::IoMode;
 use pageserver_api::shard::TenantShardId;
 use pageserver_api::value::Value;
 use tokio_util::sync::CancellationToken;
@@ -28,6 +29,7 @@ fn murmurhash32(mut h: u32) -> u32 {
     h
 }
 
+#[derive(serde::Serialize, Clone, Copy, Debug)]
 enum KeyLayout {
     /// Sequential unique keys
     Sequential,
@@ -37,6 +39,7 @@ enum KeyLayout {
     RandomReuse(u32),
 }
 
+#[derive(serde::Serialize, Clone, Copy, Debug)]
 enum WriteDelta {
     Yes,
     No,
@@ -138,12 +141,15 @@ async fn ingest(
 /// Wrapper to instantiate a tokio runtime
 fn ingest_main(
     conf: &'static PageServerConf,
+    io_mode: IoMode,
     put_size: usize,
     put_count: usize,
     key_layout: KeyLayout,
     write_delta: WriteDelta,
 ) {
-    let runtime = tokio::runtime::Builder::new_current_thread()
+    pageserver::virtual_file::set_io_mode(io_mode);
+
+    let runtime = tokio::runtime::Builder::new_multi_thread()
         .enable_all()
         .build()
         .unwrap();
@@ -174,93 +180,207 @@ fn criterion_benchmark(c: &mut Criterion) {
     virtual_file::init(
         16384,
         virtual_file::io_engine_for_bench(),
+        // immaterial, each `ingest_main` invocation below overrides this
         conf.virtual_file_io_mode,
+        // without actually doing syncs, buffered writes have an unfair advantage over direct IO writes
         virtual_file::SyncMode::Sync,
     );
     page_cache::init(conf.page_cache_size);
 
-    {
-        let mut group = c.benchmark_group("ingest-small-values");
-        let put_size = 100usize;
-        let put_count = 128 * 1024 * 1024 / put_size;
-        group.throughput(criterion::Throughput::Bytes((put_size * put_count) as u64));
-        group.sample_size(10);
-        group.bench_function("ingest 128MB/100b seq", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::Sequential,
-                    WriteDelta::Yes,
-                )
-            })
-        });
-        group.bench_function("ingest 128MB/100b rand", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::Random,
-                    WriteDelta::Yes,
-                )
-            })
-        });
-        group.bench_function("ingest 128MB/100b rand-1024keys", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::RandomReuse(0x3ff),
-                    WriteDelta::Yes,
-                )
-            })
-        });
-        group.bench_function("ingest 128MB/100b seq, no delta", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::Sequential,
-                    WriteDelta::No,
-                )
-            })
-        });
+    #[derive(serde::Serialize)]
+    struct ExplodedParameters {
+        io_mode: IoMode,
+        volume_mib: usize,
+        key_size: usize,
+        key_layout: KeyLayout,
+        write_delta: WriteDelta,
     }
-
-    {
-        let mut group = c.benchmark_group("ingest-big-values");
-        let put_size = 8192usize;
-        let put_count = 128 * 1024 * 1024 / put_size;
-        group.throughput(criterion::Throughput::Bytes((put_size * put_count) as u64));
+    #[derive(Clone)]
+    struct HandPickedParameters {
+        volume_mib: usize,
+        key_size: usize,
+        key_layout: KeyLayout,
+        write_delta: WriteDelta,
+    }
+    let expect = vec![
+        // Small values (100b) tests
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 100,
+            key_layout: KeyLayout::Sequential,
+            write_delta: WriteDelta::Yes,
+        },
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 100,
+            key_layout: KeyLayout::Random,
+            write_delta: WriteDelta::Yes,
+        },
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 100,
+            key_layout: KeyLayout::RandomReuse(0x3ff),
+            write_delta: WriteDelta::Yes,
+        },
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 100,
+            key_layout: KeyLayout::Sequential,
+            write_delta: WriteDelta::No,
+        },
+        // Large values (8k) tests
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 8192,
+            key_layout: KeyLayout::Sequential,
+            write_delta: WriteDelta::Yes,
+        },
+        HandPickedParameters {
+            volume_mib: 128,
+            key_size: 8192,
+            key_layout: KeyLayout::Sequential,
+            write_delta: WriteDelta::No,
+        },
+    ];
+    let exploded_parameters = {
+        let mut out = Vec::new();
+        for io_mode in [
+            IoMode::Buffered,
+            #[cfg(target_os = "linux")]
+            IoMode::Direct,
+        ] {
+            for param in expect.clone() {
+                let HandPickedParameters {
+                    volume_mib,
+                    key_size,
+                    key_layout,
+                    write_delta,
+                } = param;
+                out.push(ExplodedParameters {
+                    io_mode,
+                    volume_mib,
+                    key_size,
+                    key_layout,
+                    write_delta,
+                });
+            }
+        }
+        out
+    };
+    impl ExplodedParameters {
+        fn benchmark_id(&self) -> String {
+            let ExplodedParameters {
+                io_mode,
+                volume_mib,
+                key_size,
+                key_layout,
+                write_delta,
+            } = self;
+            format!(
+                "io_mode={io_mode:?} volume_mib={volume_mib:?} key_size_bytes={key_size:?} key_layout={key_layout:?} write_delta={write_delta:?}"
+            )
+        }
+    }
+    let mut group = c.benchmark_group("ingest");
+    for params in exploded_parameters {
+        let id = params.benchmark_id();
+        let ExplodedParameters {
+            io_mode,
+            volume_mib,
+            key_size,
+            key_layout,
+            write_delta,
+        } = params;
+        let put_count = volume_mib * 1024 * 1024 / key_size;
+        group.throughput(criterion::Throughput::Bytes((key_size * put_count) as u64));
         group.sample_size(10);
-        group.bench_function("ingest 128MB/8k seq", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::Sequential,
-                    WriteDelta::Yes,
-                )
-            })
-        });
-        group.bench_function("ingest 128MB/8k seq, no delta", |b| {
-            b.iter(|| {
-                ingest_main(
-                    conf,
-                    put_size,
-                    put_count,
-                    KeyLayout::Sequential,
-                    WriteDelta::No,
-                )
-            })
+        group.bench_function(id, |b| {
+            b.iter(|| ingest_main(conf, io_mode, key_size, put_count, key_layout, write_delta))
         });
     }
 }
 
 criterion_group!(benches, criterion_benchmark);
 criterion_main!(benches);
+
+/*
+cargo bench --bench bench_ingest
+
+im4gn.2xlarge:
+
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=Yes
+                        time:   [1.8491 s 1.8540 s 1.8592 s]
+                        thrpt:  [68.847 MiB/s 69.039 MiB/s 69.222 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Random write_delta=Yes
+                        time:   [2.6976 s 2.7123 s 2.7286 s]
+                        thrpt:  [46.911 MiB/s 47.193 MiB/s 47.450 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=RandomReuse(1023) write_delta=Y...
+                        time:   [1.7433 s 1.7510 s 1.7600 s]
+                        thrpt:  [72.729 MiB/s 73.099 MiB/s 73.423 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=No
+                        time:   [499.63 ms 500.07 ms 500.46 ms]
+                        thrpt:  [255.77 MiB/s 255.96 MiB/s 256.19 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=Yes
+                        time:   [456.97 ms 459.61 ms 461.92 ms]
+                        thrpt:  [277.11 MiB/s 278.50 MiB/s 280.11 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=No
+                        time:   [158.82 ms 159.16 ms 159.56 ms]
+                        thrpt:  [802.22 MiB/s 804.24 MiB/s 805.93 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=Yes
+                        time:   [1.8856 s 1.8997 s 1.9179 s]
+                        thrpt:  [66.740 MiB/s 67.380 MiB/s 67.882 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Random write_delta=Yes
+                        time:   [2.7468 s 2.7625 s 2.7785 s]
+                        thrpt:  [46.068 MiB/s 46.335 MiB/s 46.600 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=RandomReuse(1023) write_delta=Yes
+                        time:   [1.7689 s 1.7726 s 1.7767 s]
+                        thrpt:  [72.045 MiB/s 72.208 MiB/s 72.363 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=No
+                        time:   [497.64 ms 498.60 ms 499.67 ms]
+                        thrpt:  [256.17 MiB/s 256.72 MiB/s 257.21 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=Yes
+                        time:   [493.72 ms 505.07 ms 518.03 ms]
+                        thrpt:  [247.09 MiB/s 253.43 MiB/s 259.26 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=No
+                        time:   [267.76 ms 267.85 ms 267.96 ms]
+                        thrpt:  [477.69 MiB/s 477.88 MiB/s 478.03 MiB/s]
+
+Hetzner AX102:
+
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=Yes
+                        time:   [1.0683 s 1.1006 s 1.1386 s]
+                        thrpt:  [112.42 MiB/s 116.30 MiB/s 119.82 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Random write_delta=Yes
+                        time:   [1.5719 s 1.6012 s 1.6228 s]
+                        thrpt:  [78.877 MiB/s 79.938 MiB/s 81.430 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=RandomReuse(1023) write_delta=Y...
+                        time:   [1.1095 s 1.1331 s 1.1580 s]
+                        thrpt:  [110.53 MiB/s 112.97 MiB/s 115.37 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=No
+                        time:   [303.20 ms 307.83 ms 311.90 ms]
+                        thrpt:  [410.39 MiB/s 415.81 MiB/s 422.16 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=Yes
+                        time:   [406.34 ms 429.37 ms 451.63 ms]
+                        thrpt:  [283.42 MiB/s 298.11 MiB/s 315.00 MiB/s]
+ingest/io_mode=Buffered volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=No
+                        time:   [134.01 ms 135.78 ms 137.48 ms]
+                        thrpt:  [931.03 MiB/s 942.68 MiB/s 955.12 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=Yes
+                        time:   [1.0406 s 1.0580 s 1.0772 s]
+                        thrpt:  [118.83 MiB/s 120.98 MiB/s 123.00 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Random write_delta=Yes
+                        time:   [1.5059 s 1.5339 s 1.5625 s]
+                        thrpt:  [81.920 MiB/s 83.448 MiB/s 84.999 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=RandomReuse(1023) write_delta=Yes
+                        time:   [1.0714 s 1.0934 s 1.1161 s]
+                        thrpt:  [114.69 MiB/s 117.06 MiB/s 119.47 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=100 key_layout=Sequential write_delta=No
+                        time:   [262.68 ms 265.14 ms 267.71 ms]
+                        thrpt:  [478.13 MiB/s 482.76 MiB/s 487.29 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=Yes
+                        time:   [375.19 ms 393.80 ms 411.40 ms]
+                        thrpt:  [311.14 MiB/s 325.04 MiB/s 341.16 MiB/s]
+ingest/io_mode=Direct volume_mib=128 key_size_bytes=8192 key_layout=Sequential write_delta=No
+                        time:   [123.02 ms 123.85 ms 124.66 ms]
+                        thrpt:  [1.0027 GiB/s 1.0093 GiB/s 1.0161 GiB/s]
+*/
diff --git a/pageserver/src/virtual_file.rs b/pageserver/src/virtual_file.rs
index 45cd0f469b..4eb968c340 100644
--- a/pageserver/src/virtual_file.rs
+++ b/pageserver/src/virtual_file.rs
@@ -1369,7 +1369,7 @@ pub(crate) type IoPageSlice<'a> =
 static IO_MODE: once_cell::sync::Lazy<AtomicU8> =
     once_cell::sync::Lazy::new(|| AtomicU8::new(IoMode::preferred() as u8));
 
-pub(crate) fn set_io_mode(mode: IoMode) {
+pub fn set_io_mode(mode: IoMode) {
     IO_MODE.store(mode as u8, std::sync::atomic::Ordering::Relaxed);
 }