diff --git a/weed/s3api/s3api_object_handlers_copy.go b/weed/s3api/s3api_object_handlers_copy.go
index 634c7aed4..01b764d0c 100644
--- a/weed/s3api/s3api_object_handlers_copy.go
+++ b/weed/s3api/s3api_object_handlers_copy.go
@@ -1003,7 +1003,7 @@ func (s3a *S3ApiServer) CopyObjectPartHandler(w http.ResponseWriter, r *http.Req
 	}
 
 	if uploadEntryHasSSE(uploadEntry) || sourceEntryHasSSE(entry) || uploadEntryHasChecksum(uploadEntry) {
-		etag, sseMetadata, errCode := s3a.copyObjectPartViaReencryption(r, entry, startOffset, endOffset, dstBucket, uploadID, partID, uploadEntry)
+		etag, sseMetadata, errCode := s3a.copyObjectPartViaReencryption(r, entry, startOffset, endOffset, dstBucket, dstObject, uploadID, partID, uploadEntry)
 		if errCode != s3err.ErrNone {
 			s3err.WriteErrorResponse(w, r, errCode)
 			return
@@ -1040,14 +1040,16 @@ func (s3a *S3ApiServer) CopyObjectPartHandler(w http.ResponseWriter, r *http.Req
 		Extended: make(map[string][]byte),
 	}
 
-	// The copied part lives under the destination bucket's .uploads folder.
-	// Assign destination volumes against that real filer path so they land in
-	// the destination bucket's collection. r.URL.Path is the S3 request URI
-	// (e.g. /bucket/key), not a filer path, so passing it would skip the
-	// filer's bucket-to-collection mapping and route the copied bytes to the
-	// default collection.
 	uploadDir, partName := s3a.copyPartLocation(dstBucket, uploadID, partID)
-	dstPartPath := uploadDir + "/" + partName
+
+	// The copied part entry lives under the destination bucket's .uploads
+	// folder, but its bytes become the object, so assign destination volumes
+	// against the destination object's filer path: that is the path filer.conf
+	// storage rules and the bucket-to-collection mapping are written for.
+	// r.URL.Path is the S3 request URI (e.g. /bucket/key), not a filer path, so
+	// passing it would skip the mapping and route the copied bytes to the
+	// default collection.
+	dstAssignPath := s3a.toFilerPath(dstBucket, dstObject)
 
 	// Handle zero-size files or empty ranges
 	if entry.Attributes.FileSize == 0 || endOffset < startOffset {
@@ -1056,7 +1058,7 @@ func (s3a *S3ApiServer) CopyObjectPartHandler(w http.ResponseWriter, r *http.Req
 		dstEntry.Chunks = nil
 	} else {
 		// Copy chunks that overlap with the range
-		dstChunks, err := s3a.copyChunksForRange(entry, startOffset, endOffset, dstPartPath)
+		dstChunks, err := s3a.copyChunksForRange(entry, startOffset, endOffset, dstAssignPath)
 		if err != nil {
 			glog.Errorf("CopyObjectPartHandler copy chunks error: %v", err)
 			s3err.WriteErrorResponse(w, r, s3err.ErrInternalError)
diff --git a/weed/s3api/s3api_object_handlers_copy_collection_test.go b/weed/s3api/s3api_object_handlers_copy_collection_test.go
index 79d0bcac6..165cea5b3 100644
--- a/weed/s3api/s3api_object_handlers_copy_collection_test.go
+++ b/weed/s3api/s3api_object_handlers_copy_collection_test.go
@@ -5,6 +5,7 @@ import (
 	"testing"
 
 	"github.com/seaweedfs/seaweedfs/weed/filer"
+	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/util"
 )
 
@@ -29,17 +30,46 @@ func TestCopyDestinationPathResolvesBucketCollection(t *testing.T) {
 		t.Fatalf("S3 request URI unexpectedly mapped to collection %q; the test no longer reproduces the bug", got)
 	}
 
-	// UploadPartCopy assigns against the destination part path under .uploads.
-	uploadDir, partName := s3a.copyPartLocation(bucket, "uploadid", 1)
-	partPath := uploadDir + "/" + partName
-	if got := f.DetectBucket(util.FullPath(partPath)); got != bucket {
-		t.Fatalf("UploadPartCopy dst path %q resolved to collection %q, want %q", partPath, got, bucket)
-	}
-
-	// CopyObject (including the SSE-C paths) assigns against the destination
-	// object path.
+	// CopyObject (including the SSE-C paths) and UploadPartCopy both assign
+	// against the destination object path.
 	objPath := fmt.Sprintf("%s/%s", s3a.bucketDir(bucket), "blobs/data")
 	if got := f.DetectBucket(util.FullPath(objPath)); got != bucket {
 		t.Fatalf("CopyObject dst path %q resolved to collection %q, want %q", objPath, got, bucket)
 	}
+
+	// The part entry itself still lives under .uploads, which maps to the same
+	// collection, so the entry write is unaffected either way.
+	uploadDir, partName := s3a.copyPartLocation(bucket, "uploadid", 1)
+	partPath := uploadDir + "/" + partName
+	if got := f.DetectBucket(util.FullPath(partPath)); got != bucket {
+		t.Fatalf("UploadPartCopy part path %q resolved to collection %q, want %q", partPath, got, bucket)
+	}
+}
+
+// TestMultipartStorageRuleFollowsDestinationObject guards the filer.conf storage
+// rule a multipart part's chunks are placed by.
+//
+// Parts stage under /buckets/<bucket>/.uploads/..., so a rule scoped to a key
+// prefix ("place /buckets/b/data/ on a 30d TTL volume") matches the object but
+// not the part. Assigning against the part path therefore scattered a large
+// object's bytes onto TTL-less volumes while its entry carried the rule's TTL.
+// The gateway assigns against the destination object instead, the way the
+// x-seaweedfs-destination header made the filer resolve it before the S3 write
+// path moved off the filer proxy.
+func TestMultipartStorageRuleFollowsDestinationObject(t *testing.T) {
+	const bucket, object = "b", "/data/big.bin"
+	s3a := &S3ApiServer{option: &S3ApiServerOption{BucketsPath: "/buckets"}}
+	fc := filer.NewFilerConf()
+	fc.AddLocationConf(&filer_pb.FilerConf_PathConf{LocationPrefix: "/buckets/b/data/", Ttl: "30d"})
+
+	partPath := s3a.genPartUploadPath(bucket, "uploadid", 1)
+	if got := fc.MatchStorageRule(partPath).GetTtl(); got != "" {
+		t.Fatalf("part path %q matched ttl %q; the test no longer reproduces the gap", partPath, got)
+	}
+
+	// What PutObjectPart and UploadPartCopy now assign against.
+	dstPath := s3a.toFilerPath(bucket, object)
+	if got := fc.MatchStorageRule(dstPath).GetTtl(); got != "30d" {
+		t.Fatalf("destination path %q resolved ttl %q, want 30d", dstPath, got)
+	}
 }
diff --git a/weed/s3api/s3api_object_handlers_copy_part_sse.go b/weed/s3api/s3api_object_handlers_copy_part_sse.go
index 163543212..a7887d850 100644
--- a/weed/s3api/s3api_object_handlers_copy_part_sse.go
+++ b/weed/s3api/s3api_object_handlers_copy_part_sse.go
@@ -364,7 +364,7 @@ func (s3a *S3ApiServer) copyObjectPartViaReencryption(
 	r *http.Request,
 	srcEntry *filer_pb.Entry,
 	startOffset, endOffset int64,
-	dstBucket, uploadID string,
+	dstBucket, dstObject, uploadID string,
 	partID int,
 	uploadEntry *filer_pb.Entry,
 ) (etag string, sseMetadata SSEResponseMetadata, errCode s3err.ErrorCode) {
@@ -399,7 +399,7 @@ func (s3a *S3ApiServer) copyObjectPartViaReencryption(
 	applyDestChecksumHeaderToCopyRequest(cloned, uploadEntry)
 
 	filePath := s3a.genPartUploadPath(dstBucket, uploadID, partID)
-	tag, code, putSSE := s3a.putToFiler(cloned, filePath, srcReader, dstBucket, "", partID, 0, nil, false)
+	tag, code, putSSE := s3a.putToFiler(cloned, filePath, srcReader, dstBucket, "", partID, 0, nil, false, s3a.toFilerPath(dstBucket, dstObject))
 	if code != s3err.ErrNone {
 		return "", SSEResponseMetadata{}, code
 	}
diff --git a/weed/s3api/s3api_object_handlers_multipart.go b/weed/s3api/s3api_object_handlers_multipart.go
index 8b7b6b05b..defdfbbd2 100644
--- a/weed/s3api/s3api_object_handlers_multipart.go
+++ b/weed/s3api/s3api_object_handlers_multipart.go
@@ -459,8 +459,9 @@ func (s3a *S3ApiServer) PutObjectPartHandler(w http.ResponseWriter, r *http.Requ
 	// volume TTL: the rule targets the user-visible object, not the
 	// transient .uploads/<id>/<n> path, and a part write would otherwise
 	// start the TTL clock before CompleteMultipartUpload ever assembled
-	// the object.
-	etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, dataReader, bucket, "", partID, 0, nil, false)
+	// the object. filer.conf storage rules are the opposite case: they
+	// place the bytes the part becomes, so they resolve against the object.
+	etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, dataReader, bucket, "", partID, 0, nil, false, s3a.toFilerPath(bucket, object))
 	if errCode != s3err.ErrNone {
 		glog.Errorf("PutObjectPart: putToFiler failed with error code %v for bucket=%s, object=%s, partNumber=%d",
 			errCode, bucket, object, partID)
diff --git a/weed/s3api/s3api_object_handlers_postpolicy.go b/weed/s3api/s3api_object_handlers_postpolicy.go
index ce3d74d69..84fc7eb2f 100644
--- a/weed/s3api/s3api_object_handlers_postpolicy.go
+++ b/weed/s3api/s3api_object_handlers_postpolicy.go
@@ -140,7 +140,7 @@ func (s3a *S3ApiServer) PostPolicyBucketHandler(w http.ResponseWriter, r *http.R
 	// fields and boundaries inflates ContentLength relative to the
 	// object body, which would mis-evaluate any size-filtered rule.
 	ttlSec := s3a.lifecycleTTLForObjectWrite(bucket, object, fileSize)
-	etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, fileBody, bucket, object, 1, ttlSec, nil, false)
+	etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, fileBody, bucket, object, 1, ttlSec, nil, false, "")
 
 	if errCode != s3err.ErrNone {
 		s3err.WriteErrorResponse(w, r, errCode)
diff --git a/weed/s3api/s3api_object_handlers_put.go b/weed/s3api/s3api_object_handlers_put.go
index 6c56dc210..3ecb83c35 100644
--- a/weed/s3api/s3api_object_handlers_put.go
+++ b/weed/s3api/s3api_object_handlers_put.go
@@ -308,7 +308,7 @@ func (s3a *S3ApiServer) PutObjectHandler(w http.ResponseWriter, r *http.Request)
 			}
 
 			ttlSec := s3a.lifecycleTTLForObjectWrite(bucket, object, r.ContentLength)
-			etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, dataReader, bucket, object, 1, ttlSec, nil, false)
+			etag, errCode, sseMetadata := s3a.putToFiler(r, filePath, dataReader, bucket, object, 1, ttlSec, nil, false, "")
 
 			if errCode != s3err.ErrNone {
 				s3err.WriteErrorResponse(w, r, errCode)
@@ -402,7 +402,12 @@ func (s3a *S3ApiServer) uploadChunkSize() int32 {
 // pass 0 because their own keys aren't the user-visible object the rule
 // targets and a part write would otherwise bind a TTL clock starting
 // before CompleteMultipartUpload.
-func (s3a *S3ApiServer) putToFiler(r *http.Request, filePath string, dataReader io.Reader, bucket string, object string, partNumber int, lifecycleTTLSec int32, finalize *putFinalize, uniqueWritePath bool) (etag string, code s3err.ErrorCode, sseMetadata SSEResponseMetadata) {
+//
+// storageDestination overrides the path the filer resolves filer.conf storage
+// rules against, empty meaning filePath. MPU parts stage under the bucket's
+// .uploads folder but their bytes become the object, so they pass the object's
+// path the way the x-seaweedfs-destination header used to carry it.
+func (s3a *S3ApiServer) putToFiler(r *http.Request, filePath string, dataReader io.Reader, bucket string, object string, partNumber int, lifecycleTTLSec int32, finalize *putFinalize, uniqueWritePath bool, storageDestination string) (etag string, code s3err.ErrorCode, sseMetadata SSEResponseMetadata) {
 	if !s3_constants.IsValidBucketName(bucket) || (object != "" && !s3_constants.IsValidObjectKey(object)) {
 		return "", s3err.ErrInvalidRequest, SSEResponseMetadata{}
 	}
@@ -506,6 +511,11 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, filePath string, dataReader
 		collection = s3a.getCollectionName(bucket)
 	}
 
+	assignPath := filePath
+	if storageDestination != "" {
+		assignPath = storageDestination
+	}
+
 	// Create assign function for chunked upload
 	assignFunc := func(ctx context.Context, count int, expectedDataSize uint64) (*operation.VolumeAssignRequest, *operation.AssignResult, error) {
 		var assignResult *filer_pb.AssignVolumeResponse
@@ -516,7 +526,7 @@ func (s3a *S3ApiServer) putToFiler(r *http.Request, filePath string, dataReader
 				Collection:       collection,
 				DiskType:         "",
 				DataCenter:       s3a.option.DataCenter,
-				Path:             filePath,
+				Path:             assignPath,
 				ExpectedDataSize: expectedDataSize,
 				TtlSec:           lifecycleTTLSec,
 			})
@@ -1382,7 +1392,7 @@ func (s3a *S3ApiServer) putSuspendedVersioningObject(r *http.Request, bucket, ob
 			}
 			return s3err.ErrNone
 		},
-	}, false)
+	}, false, "")
 	if errCode != s3err.ErrNone {
 		glog.Errorf("putSuspendedVersioningObject: failed to upload object: %v", errCode)
 		return "", errCode, SSEResponseMetadata{}
@@ -1572,7 +1582,7 @@ func (s3a *S3ApiServer) putVersionedObject(r *http.Request, bucket, object strin
 	// directly — versioned objects sit on regular volumes and the
 	// lifecycle worker handles their expiration.
 	etag, errCode, sseMetadata = s3a.putToFiler(r, versionFilePath, body, bucket, normalizedObject, 1, 0,
-		s3a.versionedFinalize(bucket, normalizedObject, versionId, versionFileName, useInvertedFormat), true)
+		s3a.versionedFinalize(bucket, normalizedObject, versionId, versionFileName, useInvertedFormat), true, "")
 	if errCode != s3err.ErrNone {
 		glog.Errorf("putVersionedObject: failed to upload version: %v", errCode)
 		return "", "", errCode, SSEResponseMetadata{}