Restic forget and external HDD


I have a question about restic “forget”.

I’ve set up a cronjob such that restic backs up my dropbox, some local folders, and an external hard drive (if it’s present). The snapshot is pushed to an s3 bucket.

Due to a lack of available ports my external hard drive is not always plugged in. Some snapshots will therefore not include the external HDD.

When the backup completes I run

restic forget --keep-daily 7 --keep-weekly 4 --keep-monthly 12 --keep-yearly 7


restic prune

Am I right in my assumption that restic forget could pick all the snapshots that don’t have the HDD? Is there a more appropriate approach for this situation?


You are right. A better approach would be to make separate snapshots which only contain your external hard drive. This means your cronjob should run two restic backup commands. Run the backup command to backup your external disc only if it is mounted, e.g. by checking /proc/mounts.

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Thanks for coming back @alexweiss .

Just to be 100% clear. If my current command is:

restic backup "$DROPBOX" "$EXT_HDD" --verbose

you’re proposing I instead go for two sequential commands i.e.

restic backup "$DROPBOX" --verbose 

if $EXT_HDD present: # pseudocode
    restic backup "$EXT_HDD" --verbose 

and that will avoid the danger of restic forget killing $EXT_HDD if it hasn’t been backed up in a long while?

That’s exactly what I am proposing :smile:

forget will then apply the policy for each group of snapshots individually. Or you run two forget runs with --path specified.

A side remark: you can also run several backup commands in parallel.

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