diff --git a/seaweed-volume/src/server/grpc_server.rs b/seaweed-volume/src/server/grpc_server.rs
index 46daeff0e..97882ba9b 100644
--- a/seaweed-volume/src/server/grpc_server.rs
+++ b/seaweed-volume/src/server/grpc_server.rs
@@ -515,7 +515,7 @@ impl VolumeServer for VolumeGrpcService {
             collection: vol.collection.clone(),
             replication: vol.super_block.replica_placement.to_string(),
             ttl: vol.super_block.ttl.to_string(),
-            tail_offset: vol.content_size(),
+            tail_offset: vol.dat_file_size().unwrap_or(0),
             compact_revision: vol.super_block.compaction_revision as u32,
             idx_file_size: vol.idx_file_size(),
             version: vol.version().0 as u32,
diff --git a/test/volume_server/grpc/copy_sync_test.go b/test/volume_server/grpc/copy_sync_test.go
index 9678efe4b..810395fb6 100644
--- a/test/volume_server/grpc/copy_sync_test.go
+++ b/test/volume_server/grpc/copy_sync_test.go
@@ -22,8 +22,15 @@ func TestVolumeSyncStatusAndReadVolumeFileStatus(t *testing.T) {
 	conn, grpcClient := framework.DialVolumeServer(t, clusterHarness.VolumeGRPCAddress())
 	defer conn.Close()
 
+	httpClient := framework.NewHTTPClient()
 	const volumeID = uint32(41)
 	framework.AllocateVolume(t, grpcClient, volumeID, "")
+	fid := framework.NewFileID(volumeID, 1, 0x11112222)
+	uploadResp := framework.UploadBytes(t, httpClient, clusterHarness.VolumeAdminURL(), fid, []byte("sync-status-payload"))
+	_ = framework.ReadAllAndClose(t, uploadResp)
+	if uploadResp.StatusCode != http.StatusCreated {
+		t.Fatalf("upload expected 201, got %d", uploadResp.StatusCode)
+	}
 
 	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
 	defer cancel()
@@ -46,6 +53,12 @@ func TestVolumeSyncStatusAndReadVolumeFileStatus(t *testing.T) {
 	if statusResp.GetVersion() == 0 {
 		t.Fatalf("ReadVolumeFileStatus expected non-zero version")
 	}
+	if syncResp.GetTailOffset() == 0 {
+		t.Fatalf("VolumeSyncStatus expected non-zero tail offset after upload")
+	}
+	if syncResp.GetTailOffset() != statusResp.GetDatFileSize() {
+		t.Fatalf("VolumeSyncStatus tail offset mismatch: got %d want %d", syncResp.GetTailOffset(), statusResp.GetDatFileSize())
+	}
 }
 
 func TestCopyAndStreamMethodsMissingVolumePaths(t *testing.T) {