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E2MMPSTATUS(8)		    System Manager's Manual		E2MMPSTATUS(8)

NAME
       e2mmpstatus - Check MMP status of an ext4 file system

SYNOPSIS
       e2mmpstatus [-i]	<filesystem_

OPTIONS
       -i     prints out the MMP information rather than check it.

DESCRIPTION
       e2mmpstatus  is used to check Multiple-Mount Protection (MMP) status of
       an ext4 file system with	the mmp	feature	enabled.  The  specified  file
       system  can  be	a device name (e.g.  /dev/hdc1,	/dev/sdb2), or an ext4
       file	 system	     label	or	 UUID,	     for       example
       UUID=8868abf6-88c5-4a83-98b8-bfc24057f7bd  or  LABEL=root.  By default,
       the e2mmpstatus program checks whether it is safe  to  mount  the  file
       system without taking the risk of mounting it more than once.

       MMP  (multiple-mount  protection)  is  a	 feature  that adds protection
       against the file	system being modified simultaneously by	more than  one
       node.   It is NOT safe to mount a file system when one of the following
       conditions is true:
	    1. e2fsck is running on the	file system.
	    2. the file	system is in use by another node.
	    3. The MMP block is	corrupted or cannot be read for	some reason.
       The e2mmpstatus program might wait for some time	to see whether the MMP
       block  is being updated by any node during this period.	The time taken
       depends on how frequently the MMP block is being	written	by  the	 other
       node.

EXIT CODE
       The exit	code returned by e2mmpstatus is	0 when it is safe to mount the
       file system, 1 when the MMP block shows the file	system is  in  use  on
       another node and	it is NOT safe to mount	the file system, and 2 if some
       other failure occurred that prevents the	check from properly  detecting
       the current MMP status.

SEE ALSO
       dumpe2fs(8), e2fsck(8), fstab(5), fsck(8),

E2fsprogs version 1.46.4	  August 2021			E2MMPSTATUS(8)

NAME | SYNOPSIS | OPTIONS | DESCRIPTION | EXIT CODE | SEE ALSO

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