The fsfreeze command, is used to suspend and resume access to a file system. This allows consistent snapshots to be taken of the filesystem. fsfreeze supports Ext3/4, ReiserFS, JFS and XFS.
A filesystem can be frozen using following command:
# /sbin/fsfreeze -f /data
Now if you are writing to this filesystem, the process/command will be stuck. For example, following command will be stuck in D (UNINTERUPTEBLE_SLEEP) state:
# echo “testing” > /data/file
Only after the filesystem is unfreezed using the following command, can it continue:
# /sbin/fsfreeze -u /data
As per the fsfreeze main page, …[Read more...]