change the basic unit to MB

weed/command/compact.go

@@ -24,7 +24,7 @@ var (
 	compactVolumeCollection  = cmdCompact.Flag.String("collection", "", "volume collection name")
 	compactVolumeId          = cmdCompact.Flag.Int("volumeId", -1, "a volume id. The volume should already exist in the dir.")
 	compactMethod            = cmdCompact.Flag.Int("method", 0, "option to choose which compact method. use 0 or 1.")
-	compactVolumePreallocate = cmdCompact.Flag.Int64("preallocate", 0, "preallocate volume disk space")
+	compactVolumePreallocate = cmdCompact.Flag.Int64("preallocateMB", 0, "preallocate volume disk space")
 )
 
 func runCompact(cmd *Command, args []string) bool {
@@ -35,7 +35,7 @@ func runCompact(cmd *Command, args []string) bool {
 
 	vid := storage.VolumeId(*compactVolumeId)
 	v, err := storage.NewVolume(*compactVolumePath, *compactVolumeCollection, vid,
-		storage.NeedleMapInMemory, nil, nil, *compactVolumePreallocate)
+		storage.NeedleMapInMemory, nil, nil, *compactVolumePreallocate*(1<<20))
 	if err != nil {
 		glog.Fatalf("Load Volume [ERROR] %s\n", err)
 	}