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 exam‐
       ple  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 pe‐
       riod.  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 pre‐
       vents the check from properly detecting the current MMP status.

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

E2fsprogs version 1.47.0                                   February 2023                                             E2MMPSTATUS(8)