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 1.47.0                          February 2023                                   E2MMPSTATUS(8)