+The MDT or OST device to stop LFSCK/scrub on. If "-M" option is not specified,
+it will select the available Lustre device on current server automatically.
+But under the following cases you need to specify the device (see "-M" option)
+explicitly: if there are multiple devices on current server those belong to
+different Lustre filesystems, or if "-A" option is not specified and there are
+multiple devices on current server.