diff --git a/weed/replication/sink/filersink/fetch_write.go b/weed/replication/sink/filersink/fetch_write.go
index 07218b9b3..360a34620 100644
--- a/weed/replication/sink/filersink/fetch_write.go
+++ b/weed/replication/sink/filersink/fetch_write.go
@@ -19,17 +19,20 @@ func (fs *FilerSink) replicateChunks(sourceChunks []*filer_pb.FileChunk, dir str
 	if len(sourceChunks) == 0 {
 		return
 	}
+
+	replicatedChunks =  make([]*filer_pb.FileChunk, len(sourceChunks))
+
 	var wg sync.WaitGroup
-	for _, sourceChunk := range sourceChunks {
+	for chunkIndex, sourceChunk := range sourceChunks {
 		wg.Add(1)
-		go func(chunk *filer_pb.FileChunk) {
+		go func(chunk *filer_pb.FileChunk, index int) {
 			defer wg.Done()
 			replicatedChunk, e := fs.replicateOneChunk(chunk, dir)
 			if e != nil {
 				err = e
 			}
-			replicatedChunks = append(replicatedChunks, replicatedChunk)
-		}(sourceChunk)
+			replicatedChunks[index] = replicatedChunk
+		}(sourceChunk, chunkIndex)
 	}
 	wg.Wait()
 
diff --git a/weed/replication/sink/s3sink/s3_sink.go b/weed/replication/sink/s3sink/s3_sink.go
index 5f548559b..e0aee5ada 100644
--- a/weed/replication/sink/s3sink/s3_sink.go
+++ b/weed/replication/sink/s3sink/s3_sink.go
@@ -91,7 +91,6 @@ func (s3sink *S3Sink) DeleteEntry(key string, isDirectory, deleteIncludeChunks b
 }
 
 func (s3sink *S3Sink) CreateEntry(key string, entry *filer_pb.Entry) error {
-
 	key = cleanKey(key)
 
 	if entry.IsDirectory {
@@ -106,19 +105,20 @@ func (s3sink *S3Sink) CreateEntry(key string, entry *filer_pb.Entry) error {
 	totalSize := filer2.TotalSize(entry.Chunks)
 	chunkViews := filer2.ViewFromChunks(entry.Chunks, 0, int(totalSize))
 
-	var parts []*s3.CompletedPart
+	parts := make([]*s3.CompletedPart, len(chunkViews))
+
 	var wg sync.WaitGroup
 	for chunkIndex, chunk := range chunkViews {
 		partId := chunkIndex + 1
 		wg.Add(1)
-		go func(chunk *filer2.ChunkView) {
+		go func(chunk *filer2.ChunkView, index int) {
 			defer wg.Done()
 			if part, uploadErr := s3sink.uploadPart(key, uploadId, partId, chunk); uploadErr != nil {
 				err = uploadErr
 			} else {
-				parts = append(parts, part)
+				parts[index] = part
 			}
-		}(chunk)
+		}(chunk, chunkIndex)
 	}
 	wg.Wait()