mount: optional limit for the number of concurrent writers

weed/command/mount.go

@@ -14,6 +14,7 @@ type MountOptions struct {
 	replication                 *string
 	ttlSec                      *int
 	chunkSizeLimitMB            *int
+	concurrentWriters           *int
 	cacheDir                    *string
 	cacheSizeMB                 *int64
 	dataCenter                  *string
@@ -42,6 +43,7 @@ func init() {
 	mountOptions.replication = cmdMount.Flag.String("replication", "", "replication(e.g. 000, 001) to create to files. If empty, let filer decide.")
 	mountOptions.ttlSec = cmdMount.Flag.Int("ttl", 0, "file ttl in seconds")
 	mountOptions.chunkSizeLimitMB = cmdMount.Flag.Int("chunkSizeLimitMB", 2, "local write buffer size, also chunk large files")
+	mountOptions.concurrentWriters = cmdMount.Flag.Int("concurrentWriters", 0, "limit concurrent goroutine writers if not 0")
 	mountOptions.cacheDir = cmdMount.Flag.String("cacheDir", os.TempDir(), "local cache directory for file chunks and meta data")
 	mountOptions.cacheSizeMB = cmdMount.Flag.Int64("cacheCapacityMB", 1000, "local file chunk cache capacity in MB (0 will disable cache)")
 	mountOptions.dataCenter = cmdMount.Flag.String("dataCenter", "", "prefer to write to the data center")

weed/command/mount_std.go

@@ -175,6 +175,7 @@ func RunMount(option *MountOptions, umask os.FileMode) bool {
 		Replication:                 *option.replication,
 		TtlSec:                      int32(*option.ttlSec),
 		ChunkSizeLimit:              int64(chunkSizeLimitMB) * 1024 * 1024,
+		ConcurrentWriters:           *option.concurrentWriters,
 		CacheDir:                    *option.cacheDir,
 		CacheSizeMB:                 *option.cacheSizeMB,
 		DataCenter:                  *option.dataCenter,