zman

Open source tool automating ZFS snapshot creation and expiration based on a simple configuration file.

Frequency based

Snapshot creation schedule could be hourly, daily or monthly. Each of these frequency types can retain a given quantity of snapshots before expiring them.

Commands

status

Displays active and expired snapshots along with pools overdue for a new snapshot.

renew

Renews pools found in the overdue section of the status command.

purge

Destroys snapshots considered as expired based on the configuration file.

Driven by cron

Monitoring is done by calling zman on a timely basis, which could be done by simple cron jobs.

Example

0 * * * * /usr/local/sbin/zman renew
0 * * * * /usr/local/sbin/zman purge

Configuration file

By default, zman looks for it at /etc/zman/zman.yaml, but could be specified with the -c command like in this example:

zman status -c=~/zman.yaml

This configuration files contains two top level keys: zfs and pools.

• zfs: (optional) location of the zfs executable
• pools: an array of these
  • name: name of a pool to be monitored
  • frequency: array of snapshot schedules
    • type: monthly, daily or hourly
    • quantity: number of snapshots until considered expired

---
zfs: /sbin/zfs
pools:
- name: smallpool/zman
  frequencies:
    - type: monthly
      quantity: 3
    - type: daily
      quantity: 31
    - type: hourly
      quantity: 24

- name: largepool/vm-503-disk-0
  frequencies:
    - type: daily
      quantity: 31
    - type: hourly
      quantity: 24

In this example, zman monitors two pools: smallpool/zman and largepool/vm-503-disk-0.

smallpool/zman

This configuration will snapshot the pool every hour, keeping each of those for a day. Other snapshots are taken every day, keeping them longer, for a period of 31 days. It is also snapshotting once a month, keeping those for a bit longer: 3 months.

largepool/whatever

Same snapshot strategy as smallpool/zman but no monthly schedule.