zfsdesnap

Tool to destroy all ZFS snapshots before a certain date, based off a configurable name and date format. Written in bourne shell.

Commandline Flags

• -p Running with a prefix.
• -d Date snapshots should be destroyed before.
• -n (Optional) Run in test mode, will not destroy anything.
• -a (Optional) Ask before destroying snapshot.
• -r (Optional) Run only on specified dataset.
• -f (Optional) Set format of date. Uses grep syntax [[:digit:]]{n}. Default is set to:[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}-[[:digit:]]{6}.

Usage

To use the script, name snapshots in the format zpool@${prefix}-$(date +%Y-%m-%d-%H%M%S), then call zfsdesnap with a specified date that all snapshots should be destroyed before. Optionally a specific dataset can be given with -d, prefix with -p, and with -f the format of date to look for can be changed.

Examples

For example, to destroy all snapshots with the prefix "pre-install":

Destroy all snapshots with the prefix "pre-install" that are over a week old.

zfsdesnap -p "pre-install" -d "$(date -d '1 week ago' +%Y-%m-%d-%H%M%S)"
Running in test mode, will not destroy anything
Running with prefix: pre-install
Date: 2016-09-18-171206
2016-09-18-171206
Date 2016-09-18-171206 accepted
Destroy before date was set to 2016-09-18-171206
Removing hyphens
Destroydate: 20160918171206
Running on all datasets

Too use a different date format it can be specified with id. For example, to specify older than a week ago in format year-month-day:

zfsdesnap -p "pre-install" -d "$(date -d '1 week ago' +%Y-%m-%d)" -f "[[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}"
Running in test mode, will not destroy anything
Running with prefix: pre-install
Date: 2016-09-18
Date format: [[:digit:]]{4}-[[:digit:]]{2}-[[:digit:]]{2}
2016-09-18
Date 2016-09-18 accepted
Destroy before date was set to 2016-09-18
Removing hyphens
Destroydate: 20160918
Running on all datasets

systemd Units

To use routinely with the provided systemd units, move them into the location your system keeps user units in, most likely /etc/systemd/system.

Next specify each prefix you would like to be delete and start or enable the timer.

So for the prefix "pre-install":

systemctl enable zfsdesnap-week@pre-install.timer

There are provided units for snapshots a week, zfsdesnap-week@, month zfsdesnap-month@, and year zfsdesnap-year@ old.