[CE 25.x and CE 27] Stategies to Auto-Delete Old Auto-Generated Time Machine Snapshots?

TrueNAS General
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1

I’m using the Time Machine purpose with an SMB share created to be a Time Machine backup destination, and it works great (so far). (I’ve got some thoughts on the performance with the default dataset sync settings, but that’s for another post.)

I have it set to auto-generate a snapshot when it completes a Time Machine backup. Those are, of course, manual snapshots, so they’re set to live forever. Behold:

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So, I need a way to manage these in an at least semi-automated way. I have a purging schedule in mind, but (quite reasonably), there’s not an obvious built-in way to auto-delete manual snapshots that are set to be immortal.

So, before I go about figuring out how to write a script to use the CLI to delete manual snapshots on a schedule using cron or something else that’s likely to lead to exciting adventures at my current skill level, is there a recommended way to automate this sort of thing?

@HoneyBadger , if there’s an existing solution to this, it might make for a fun segment on T3. :slight_smile:

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Can you do it from the Mac system itself via tmutil?

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I don’t believe that would remove manual ZFS snaphsots taken by TrueNAS, unfortunately.

Time Machine has no awareness of what’s going on on the TrueNAS backend. :frowning:

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I have been using it for years now.

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I may be wrong but I think these automated snapshots are driven by the tmprotectSamba VFS module and retention is set to 7 days.

I tried to find this information from the official documentation, but could only find a reference from this post: