Hi all,

I had an issue with my Appcache pool (used for Docker) running slowly so I rebooted the server, but when trying to start the array, the pool drive was stuck as 'Mounting'. I ran a SMART test and it came back fine, but it was still stuck as 'Mounting'. In my infinite wisdom I tried to add it to the array pool but even then it was still stuck as mounting. Now I'm left with no working Appcache pool and cannot start my array at all as it's expecting the drive to be in the pool (whoops). How can I remove it from the Array and see what the issue is so I can either re-create the pool or fix the mounting issue?

Do a new config (tools - new config - keep all - apply) to reset disk2, then start the array and post the diagnostics after it gets stuck mounting.

Ran the new config and started the array, diagnostics attached.

tower-diagnostics-20251021-2012.zip

There's a problem with the zfs pool, reboot and then see if it imports read-only, before array start type:

zpool import -o readonly=on appcache

If that works, start the array, that pool will show as unmountable on the GUI, but the data should be under /mnt/appcache, then backup and reformat the pool.

It did (eventually) import as read-only. I was able to move the data over to another drive, then both erased and re-formatted the pool, but it still stuck as mounting, so I formatted the drive and it was able to mount correctly. Are there any other tests I should run on the drive before continuing to use it? The SMART tests came back fine so I'm not sure what would cause the issue other than something on the drive itself.

That's likely not a device problem; it may be worth running memtest to rule out any obvious RAM issues.