Manual: e2mmpstatus

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

NAME
       e2mmpstatus - Check MMP status of an ext4 file system

SYNOPSIS
       e2mmpstatus [-i] 

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 en‐
       abled.  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  simultane‐
       ously 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 oc‐
       curred that prevents the check from properly detecting the current MMP status.

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

E2fsprogs version 1.47.2				January 2025					      E2MMPSTATUS(8)