How to set forget policy for all snapshots in repo?

[the-emerald]

Hi there!

Is it possible to set the repo-wide forget policy to not use "group-by tags"? e.g.

[restic] 16:00:00.028Z	debug	command: "/bin/restic forget --json --keep-last 7 -o sftp.args=-oBatchMode=yes --group-by tags"

I have a backup script that scans ZFS snapshots and tags each snapshot with the name of the ZFS counterpart, something like this:

ID        Time                 Host            Tags                                   Paths                 Size
----------------------------------------------------------------------------------------------------------------------
62c32030  2026-06-01 00:05:02  assault-pillow  challenger/data@auto-2026-06-01_00-00  /mnt/challenger/data  12.378 TiB
3b1027ba  2026-06-02 00:05:25  assault-pillow  challenger/data@auto-2026-06-02_00-00  /mnt/challenger/data  12.378 TiB
ad905638  2026-06-03 00:05:24  assault-pillow  challenger/data@auto-2026-06-03_00-00  /mnt/challenger/data  12.378 TiB
48b33f16  2026-06-04 00:05:24  assault-pillow  challenger/data@auto-2026-06-04_00-00  /mnt/challenger/data  12.378 TiB
d3154614  2026-06-05 00:05:24  assault-pillow  challenger/data@auto-2026-06-05_00-00  /mnt/challenger/data  12.380 TiB

and I can't set it up such that I retain the last 7 backups in the repository, regardless of tag contents.

Thanks!

[krotname]

From the current code, I don't think this is configurable for the repo-level Forget Policy.

The repo-level scheduled forget path calls restic with --group-by tags, and the repo ForgetPolicy schema only contains schedule and retention. I don't see a field that maps to restic's group-by setting.

So with your current tagging scheme, --keep-last 7 is effectively applied per tag group. If every ZFS snapshot gets a unique tag, that prevents the behavior you want.

Practical options are:

• do not store the per-ZFS-snapshot name as a restic tag if repo-level retention should ignore it;
• keep only stable grouping tags, then let Backrest's repo-level policy handle retention;
• or run a separate restic forget outside Backrest with the exact --group-by behavior you want.

So the short answer is: not through the current Backrest repo-wide Forget Policy UI/config, unless the tagging scheme is changed.