Restic Forget

2023-11-15

restic forget removes snapshots according to a retention policy. With --prune, it also reclaims the freed space.

restic forget          \
    --prune            \
    --quiet            \
    --keep-daily  14   \
    --keep-weekly 20

The flags:

--prune — delete the data of removed snapshots from the repository, not just the snapshot records.
--quiet — less output.
--keep-daily 14 — keep one snapshot for each of the last 14 days on which a backup ran.
--keep-weekly 20 — keep one snapshot for each of the last 20 weeks.

The --keep-daily count is the part that confused me. It keeps one snapshot per day, for the last 14 days that had a backup. It does not mean that it simply keeps the 14 most recent snapshots.

Run the backup 10 times in one day: you still keep one snapshot for that day.
Run it once a day for 14 days: 14 snapshots, one per day.
On day 15, forget drops the oldest day, so you still have 14 — one for each of the last 14 days with a backup.

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