simple-snapshot-zfs

This is a simple script to create ZFS Snapshots, designed to overcome snapshots with 0 changes cluttering your snapshot list. To run, simply add script as a cron job.

If you use 3rd party programs to snapshot/restore, and use multiple snapshot policies, then don't use this script. Some 3rd party programs rely on the 0 change snapshots for their date/time stamps when running restores/clones. In my case, I only have a few datasets that I self-manage. So it works great for me, as I want to avoid the visual clutter and don't rely on 3rd party systems for snapshots or restores.

Key features

• Runs a check to see if the dataset has been written to before snapshot, using the 'written' property
• Prunes snapshots by keeping only the most recent 100 (adjustable)
• Provides output to let you know how many snaps and how much space is taken up

Usage

Update script with your dataset names, including the pool. Don't add a leading /, should look like: pool/dataset1

Run script manually or add it to a cron shedule

Sample output

Starting Snapshot 2023-03-23-23:21
_____________________________________________________________
No changes detected in pool/dataset1. No snapshot created.
Total snapshots for pool/admin: 3
Space used by snapshots for pool/dataset1: 239K
_____________________________________________________________
Snapshot created: pool/dataset1/code@2023-03-23-23:21
Total snapshots for pool/admin/code: 20
Space used by snapshots for pool/dataset1/code: 18.0M
_____________________________________________________________
No changes detected in pool/dataset2. No snapshot created.
Total snapshots for pool/admin/certs: 3
Space used by snapshots for pool/dataset2: 947K
_____________________________________________________________
No changes detected in pool/documents. No snapshot created.
Total snapshots for pool/documents: 5
Space used by snapshots for pool/documents: 17.5G
_____________________________________________________________
No changes detected in pool/documents/nextcloud. No snapshot created.
Total snapshots for pool/documents/nextcloud: 4
Space used by snapshots for pool/documents/nextcloud: 20.0G
_____________________________________________________________
----------------------------Done!----------------------------

Changelog

v0.9

Added validation for SHANPSHOT_QTY & DATASETS

Updated to use mapfile instead of readarray for SNAPSHOTS array

Added Error Checking & reporting for mapfile, zfs list, zfs get, zfs snapshot, zfs destroy

changed timestamp to include seconds to prevent duplicate snapshot names if < 1 minute between snapshots

changed snapshot name to add @simplesnap_ to differentiate from other snapshots

Made snapshot name configurable

Simplified use of Timestamp Variable in script & changed to SNAPSHOTNAME

v0.15

Address coding standards & issues

Define user configurable section, formatting

Updated Timestamp Formatting for readability

v0.10

Initial Commit