e2mmpstatus(8) — Linux manual page

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

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

NAME         top

       e2mmpstatus - Check MMP status of an ext4 filesystem

SYNOPSIS         top

       e2mmpstatus [-i] <filesystem>

OPTIONS         top

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

DESCRIPTION         top

       e2mmpstatus is used to check Multiple-Mount Protection (MMP)
       status of an ext4 filesystem with the mmp feature enabled.  The
       specified filesystem can be a device name (e.g.  /dev/hdc1,
       /dev/sdb2), or an ext4 filesystem 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 filesystem without taking the risk of mounting it more
       than once.

       MMP (multiple-mount protection) is a feature that adds protection
       against the filesystem being modified simultaneously by more than
       one node.  It is NOT safe to mount a filesystem when one of the
       following conditions is true:
            1. e2fsck is running on the filesystem.
            2. the filesystem 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         top

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

SEE ALSO         top

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

COLOPHON         top

       This page is part of the e2fsprogs (utilities for ext2/3/4
       filesystems) project.  Information about the project can be found
       at ⟨http://e2fsprogs.sourceforge.net/⟩.  It is not known how to
       report bugs for this man page; if you know, please send a mail to
       man-pages@man7.org.  This page was obtained from the project's
       upstream Git repository
       ⟨git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git⟩ on
       2021-06-20.  (At that time, the date of the most recent commit
       that was found in the repository was 2021-04-11.)  If you
       discover any rendering problems in this HTML version of the page,
       or you believe there is a better or more up-to-date source for
       the page, or you have corrections or improvements to the
       information in this COLOPHON (which is not part of the original
       manual page), send a mail to man-pages@man7.org

E2fsprogs version 1.46.2      February 2021               E2MMPSTATUS(8)

Pages that refer to this page: dumpe2fs(8)