diff --git a/weed/shell/command_volume_fsck.go b/weed/shell/command_volume_fsck.go
index 584ce722b..2b1daf97c 100644
--- a/weed/shell/command_volume_fsck.go
+++ b/weed/shell/command_volume_fsck.go
@@ -68,7 +68,7 @@ func (c *commandVolumeFsck) Do(args []string, commandEnv *CommandEnv, writer io.
 	findMissingChunksInFiler := fsckCommand.Bool("findMissingChunksInFiler", false, "see \"help volume.fsck\"")
 	findMissingChunksInFilerPath := fsckCommand.String("findMissingChunksInFilerPath", "/", "used together with findMissingChunksInFiler")
 	findMissingChunksInVolumeId := fsckCommand.Int("findMissingChunksInVolumeId", 0, "used together with findMissingChunksInFiler")
-	applyPurging := fsckCommand.Bool("reallyDeleteFromVolume", false, "<expert only!> after detection, delete missing data from volumes / delete missing file entries from filer")
+	applyPurging := fsckCommand.Bool("reallyDeleteFromVolume", false, "<expert only!> after detection, delete missing data from volumes / delete missing file entries from filer. Currently this only works with default filerGroup.")
 	c.forcePurging = fsckCommand.Bool("forcePurging", false, "delete missing data from volumes in one replica used together with applyPurging")
 	purgeAbsent := fsckCommand.Bool("reallyDeleteFilerEntries", false, "<expert only!> delete missing file entries from filer if the corresponding volume is missing for any reason, please ensure all still existing/expected volumes are connected! used together with findMissingChunksInFiler")
 	tempPath := fsckCommand.String("tempPath", path.Join(os.TempDir()), "path for temporary idx files")