The fsfreeze command is used to suspend and resume access to a file system. This allows consistent snapshots to be taken by halting any new write system calls while allowing ongoing transactions to complete.
Supported filesystems:
- Ext3
- Ext4
- ReiserFS
- JFS
- XFS
Note: fsfreeze is unnecessary for device-mapper devices. The device-mapper (and LVM) automatically freezes filesystem on the device when a snapshot creation is requested.