How does ZFS snapshots work and how would I implement a retention policy similar to OpenSolaris'?

Walter asked:

I’ve been using ZFS for a while and have snapshots piling up.

I believe I can start deleting the old snapshots, but want to be doubly sure. A ZFS snapshot would be essentially similar to a git tag where it is a read-only reference to a point in time version of the repository. The active data set would be HEAD and would remain unaffected if I delete a pointer to that point in time?

So, if that is the case, then if I want to have a 30-day retention policy, I can merely look at the creation date for the snapshot and discard anything > 30 days?

Are those assumptions accurate?

Thanks,

Walter

My answer:


That’s pretty accurate.

Consider using the sanoid tool to automate the creation and destruction of such snapshots on whatever schedule you desire.


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