diff --git a/weed/command/mount.go b/weed/command/mount.go
index bdc0638c9..594c2833e 100644
--- a/weed/command/mount.go
+++ b/weed/command/mount.go
@@ -57,7 +57,7 @@ func init() {
 	mountOptions.chunkSizeLimitMB = cmdMount.Flag.Int("chunkSizeLimitMB", 2, "local write buffer size, also chunk large files")
 	mountOptions.concurrentWriters = cmdMount.Flag.Int("concurrentWriters", 32, "limit concurrent goroutine writers")
 	mountOptions.cacheDirForRead = cmdMount.Flag.String("cacheDir", os.TempDir(), "local cache directory for file chunks and meta data")
-	mountOptions.cacheSizeMBForRead = cmdMount.Flag.Int64("cacheCapacityMB", 0, "file chunk read cache capacity in MB")
+	mountOptions.cacheSizeMBForRead = cmdMount.Flag.Int64("cacheCapacityMB", 128, "file chunk read cache capacity in MB")
 	mountOptions.cacheDirForWrite = cmdMount.Flag.String("cacheDirWrite", "", "buffer writes mostly for large files")
 	mountOptions.dataCenter = cmdMount.Flag.String("dataCenter", "", "prefer to write to the data center")
 	mountOptions.allowOthers = cmdMount.Flag.Bool("allowOthers", true, "allows other users to access the file system")