A simple snapshot rotation script for ZFS filesystems.
Unlike some example scripts found online, this one handles errors and does not continue when a command has failed.
Create and rotate up to count snapshots, where filesystem is the ZFS filesystem and name is the name of the snapshot (cycle, e.g., "hourly"):
# zfs-snapshot filesystem name count
A filesystem snapshot with the specified base name will be created. Typical snapshot base names are "hourly", "nightly", "weekly" or "monthly". Not more than count snapshots are kept, additional snapshots of this filesystem are deleted.
Example cron jobs:
@hourly /root/bin/zfs-snapshot datapool/Temp hourly 24
@midnight /root/bin/zfs-snapshot datapool/Temp nightly 31
@monthly /root/bin/zfs-snapshot datapool/Temp monthly 12
0 0 * * 1 /root/bin/zfs-snapshot datapool/Temp weekly 4
Create up to 3 named snapshots using zfs-autosnap.sh:
0 12 1 * * /root/bin/zfs-autosnap datapool/Temp 3
Named snapshots may be useful when creating backups:
toctar create -C /datapool/Temp/.zfs/snapshot/ Temp_snapshot_2020-01-01
This way, all files in the tape archive will be relative to .../snapshot/ like Temp_snapshot_2020-01-01/file.
The snapshot base name may only contain letters, digits and underscores.
In order to prevent a "Device busy" error when moving an existing snapshot, the list of snapshots is generated without directly accessing one. Even a stat would return this error in such a case.
Philip Seeger ([email protected])
Please see the file called LICENSE.