diff --git a/src/storage/s3.js b/src/storage/s3.js
index 5a06977bb..b5fedbae7 100644
--- a/src/storage/s3.js
+++ b/src/storage/s3.js
@@ -288,7 +288,7 @@ function copy(apiConfig, oldFilePath, newFilePath) {
                 }
                 ranges.push({ startBytes: cur, endBytes: entry.size-1 });
 
-                async.eachOfLimit(ranges, 5, function copyChunk(range, index, iteratorDone) {
+                async.eachOfLimit(ranges, 3, function copyChunk(range, index, iteratorDone) {
                     const partCopyParams = {
                         Bucket: apiConfig.bucket,
                         Key: path.join(newFilePath, relativePath),