e2mmpstatus (8) - Linux Man Pages
e2mmpstatus: Check MMP status of an ext4 filesystem
e2mmpstatus - Check MMP status of an ext4 filesystem
SYNOPSISe2mmpstatus [-i] <filesystem>
- prints out the MMP information rather than check it.
DESCRIPTIONe2mmpstatus 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
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.