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 1.47.3	   July 2025			E2MMPSTATUS(8)