Deleting snapshots already backed up

[leonardorame]

I'm using zelta backup since last month and it works wonderfully, but I found it naturally generates many snapshots (in my case one per day). Now I wonder what's the recommended retention time frame and how should I handle them, given that after some time there will be tons of them.

I mean, after a successful backup I end up with at least one snapshot on the local server and the same, replicated, on the remote server. Should I delete the local snapshot or keep it for some time, deleting only older ones?, also, is there a tool to automate the deletion?.

Leonardo.

[bellhyve]

Hi Leonardo,

It depends on your use case, but you're right—as long as you have one "match" (either a bookmark or snapshot that shares the same reference as one on your backup pools), you can prune anything else. zelta match will tell you what you CAN'T delete.

If you accidentally nuke all of your matches, incremental replication breaks and you'll have to do a full send.

Ideally I like to keep a few months on the source, but the main concern is capacity. ZFS performance degrades after 80% capacity, so watch that.

A "Zelta safe" pruning tool is in the works to ensure you have proper replicas, holds, and a sliding retention window.

One old but good choice is zfsnap, which does the one thing and does it pretty well.

If your OpenZFS version is reasonably up-to-date, zfs destroy -vrn ds/name@%old_snapshot_name (note the @% symbol for "this and older", and -r for recursive) will display all snapshots as old as and older than "old_snapshot_name". Whichever tool you use, do your dry runs and you'll be golden.

Here's a super simple prune dry run proof of concept: https://github.com/bellhyve/zelta/blob/dev/test/prune.sh

Daniel