diff --git a/pageserver/src/storage_sync2.rs b/pageserver/src/storage_sync2.rs
index 94216747ef..44b82a6a8c 100644
--- a/pageserver/src/storage_sync2.rs
+++ b/pageserver/src/storage_sync2.rs
@@ -612,7 +612,7 @@ impl RemoteTimelineClient {
             "file size not initialized in metadata"
         );
 
-        let relative_path = RelativePath::from_local_path(
+        let relative_path = RelativePath::strip_base_path(
             &self.conf.timeline_path(&self.timeline_id, &self.tenant_id),
             path,
         )?;
@@ -644,7 +644,7 @@ impl RemoteTimelineClient {
         // Convert the paths into RelativePaths, and gather other information we need.
         let mut relative_paths = Vec::with_capacity(paths.len());
         for path in paths {
-            relative_paths.push(RelativePath::from_local_path(
+            relative_paths.push(RelativePath::strip_base_path(
                 &self.conf.timeline_path(&self.timeline_id, &self.tenant_id),
                 path,
             )?);
diff --git a/pageserver/src/storage_sync2/index.rs b/pageserver/src/storage_sync2/index.rs
index 2d5f3b1d54..99dd2eae6a 100644
--- a/pageserver/src/storage_sync2/index.rs
+++ b/pageserver/src/storage_sync2/index.rs
@@ -18,27 +18,26 @@ use utils::lsn::Lsn;
 /// A part of the filesystem path, that needs a root to become a path again.
 #[derive(Debug, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Serialize, Deserialize)]
 #[serde(transparent)]
-pub struct RelativePath(String);
+pub struct RelativePath(PathBuf);
 
 impl RelativePath {
-    /// Attempts to strip off the base from path, producing a relative path or an error.
-    pub fn from_local_path(timeline_path: &Path, path: &Path) -> anyhow::Result<RelativePath> {
-        let relative = path.strip_prefix(timeline_path).with_context(|| {
-            format!(
-                "path '{}' is not relative to base '{}'",
-                path.display(),
-                timeline_path.display()
-            )
+    pub fn new(relative_path: &Path) -> Self {
+        debug_assert!(
+            relative_path.is_relative(),
+            "Path {relative_path:?} is not relative"
+        );
+        Self(relative_path.to_path_buf())
+    }
+
+    pub fn strip_base_path(base_path: &Path, full_path: &Path) -> anyhow::Result<Self> {
+        let relative = full_path.strip_prefix(base_path).with_context(|| {
+            format!("path {full_path:?} is not relative to base {base_path:?}",)
         })?;
-        Ok(Self::from_filename(relative))
+        Ok(Self::new(relative))
     }
 
-    pub fn from_filename(path: &Path) -> RelativePath {
-        RelativePath(path.to_string_lossy().to_string())
-    }
-
-    pub fn to_local_path(&self, timeline_path: &Path) -> PathBuf {
-        timeline_path.join(&self.0)
+    pub fn to_local_path(&self, base_path: &Path) -> PathBuf {
+        base_path.join(&self.0)
     }
 }
 
@@ -199,8 +198,8 @@ mod tests {
 
         let expected = IndexPart {
             version: 0,
-            timeline_layers: [RelativePath("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9".to_owned())].into_iter().collect(),
-            missing_layers: Some([RelativePath("not_a_real_layer_but_adding_coverage".to_owned())].into_iter().collect()),
+            timeline_layers: HashSet::from([RelativePath(PathBuf::from("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9"))]),
+            missing_layers: Some(HashSet::from([RelativePath(PathBuf::from("not_a_real_layer_but_adding_coverage"))])),
             layer_metadata: HashMap::default(),
             disk_consistent_lsn: "0/16960E8".parse::<Lsn>().unwrap(),
             metadata_bytes: [113,11,159,210,0,54,0,4,0,0,0,0,1,105,96,232,1,0,0,0,0,1,105,96,112,0,0,0,0,0,0,0,0,0,0,0,0,0,1,105,96,112,0,0,0,0,1,105,96,112,0,0,0,14,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0].to_vec(),
@@ -227,13 +226,13 @@ mod tests {
         let expected = IndexPart {
             // note this is not verified, could be anything, but exists for humans debugging.. could be the git version instead?
             version: 1,
-            timeline_layers: [RelativePath("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9".to_owned())].into_iter().collect(),
-            missing_layers: Some([RelativePath("not_a_real_layer_but_adding_coverage".to_owned())].into_iter().collect()),
+            timeline_layers: HashSet::from([RelativePath(PathBuf::from("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9"))]),
+            missing_layers: Some(HashSet::from([RelativePath(PathBuf::from("not_a_real_layer_but_adding_coverage"))])),
             layer_metadata: HashMap::from([
-                (RelativePath("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9".to_owned()), IndexLayerMetadata {
+                (RelativePath(PathBuf::from("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9")), IndexLayerMetadata {
                     file_size: Some(25600000),
                 }),
-                (RelativePath("not_a_real_layer_but_adding_coverage".to_owned()), IndexLayerMetadata {
+                (RelativePath(PathBuf::from("not_a_real_layer_but_adding_coverage")), IndexLayerMetadata {
                     // serde_json should always parse this but this might be a double with jq for
                     // example.
                     file_size: Some(9007199254741001),
@@ -263,12 +262,12 @@ mod tests {
         let expected = IndexPart {
             // note this is not verified, could be anything, but exists for humans debugging.. could be the git version instead?
             version: 1,
-            timeline_layers: [RelativePath("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9".to_owned())].into_iter().collect(),
+            timeline_layers: [RelativePath(PathBuf::from("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9"))].into_iter().collect(),
             layer_metadata: HashMap::from([
-                (RelativePath("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9".to_owned()), IndexLayerMetadata {
+                (RelativePath(PathBuf::from("000000000000000000000000000000000000-FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF__0000000001696070-00000000016960E9")), IndexLayerMetadata {
                     file_size: Some(25600000),
                 }),
-                (RelativePath("not_a_real_layer_but_adding_coverage".to_owned()), IndexLayerMetadata {
+                (RelativePath(PathBuf::from("not_a_real_layer_but_adding_coverage")), IndexLayerMetadata {
                     // serde_json should always parse this but this might be a double with jq for
                     // example.
                     file_size: Some(9007199254741001),
diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 06ddff05ea..e42e887524 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -1013,7 +1013,7 @@ impl Timeline {
         local_filenames.retain(|path| {
             let layer_metadata = index_part
                 .layer_metadata
-                .get(&RelativePath::from_filename(path))
+                .get(&RelativePath::new(path))
                 .map(LayerFileMetadata::from)
                 .unwrap_or(LayerFileMetadata::MISSING);
 
@@ -1062,7 +1062,7 @@ impl Timeline {
 
             let layer_metadata = index_part
                 .layer_metadata
-                .get(&RelativePath::from_filename(path))
+                .get(&RelativePath::new(path))
                 .map(LayerFileMetadata::from)
                 .unwrap_or(LayerFileMetadata::MISSING);
 
@@ -1077,7 +1077,7 @@ impl Timeline {
 
                 trace!("downloading image file: {}", path.display());
                 let sz = remote_client
-                    .download_layer_file(&RelativePath::from_filename(path), &layer_metadata)
+                    .download_layer_file(&RelativePath::new(path), &layer_metadata)
                     .await
                     .context("download image layer")?;
                 trace!("done");
@@ -1107,7 +1107,7 @@ impl Timeline {
 
                 trace!("downloading delta file: {}", path.display());
                 let sz = remote_client
-                    .download_layer_file(&RelativePath::from_filename(path), &layer_metadata)
+                    .download_layer_file(&RelativePath::new(path), &layer_metadata)
                     .await
                     .context("download delta layer")?;
                 trace!("done");