Hi, I recently saw that the pool of my apps is way more used than it should. After some digging, I found out that the issue was that I had almost 150GB of unused docker images sitting in the .ix-apps inside /mnt. When I made some cleanup with docker image prune and docker system prune, the du comman…

You’re looking at wrong property for snapshots. C.f. used, written, written@snapshot zfsprops.7 — OpenZFS documentation If you have snapshots of the dataset container the data you deleted, then you need to delete all of the snapshots referencing that data before space is actually freed.

Du recurses filesystem and calculates based on files located there. It won’t show space consumed by snapshots for instance. zfs list -o space gives better view of how space is used.

[image] awalkerix: zfs list -o space Thank you for your response, here is the result of that command : FastBoy 108G 324G 0B 96K 0B 324G FastBoy/GitlabRunnerSSD-qjyli …

[image] Jox: FastBoy/ix-apps/docker 108G 142G 125G 17.1G 0B 0B You omitted the column headings in your copy-paste. Can you put them on?

root@truenas:/# zfs list -o space NAME AVAIL USED USEDSNAP USEDDS USEDREFRESERV USEDCHILD FastBoy/ix-apps/docker 108G 142G 125G 17.1G 0B …

So as you can see in your output you have 125G used by snapshots. The UI is correct. zfsconcepts.7 — OpenZFS documentation

Okay I see. I don’t really know why this snapshot does not appear in the GUI under the snapshots page. Can I remove it in some way ? Thanks a lot for your answers

Also, it does not appear when listing snapshots for that path or when sorting all the snapshots by size: zfs list -r -t snapshot -o name,creation,used -s used NAME CREATION …

Thanks a lot, that was indeed the issue I was confused (and still kinda am) by the used vs referenced parameter. I identified the snapshots and deleted them, the space usage is now shown correct again.

Wrong space summary in the GUI after docker prune

TrueNAS General

winnielinnie March 15, 2025, 12:47pm 14

You might find this helpful. It also illustrates why you need to remove all snapshots (“colored sticker sets”) in order to free up more space.

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Wrong space summary in the GUI after docker prune

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