Since I have misunderstood before, I'll check before I begin.

You're saying appdata, domains, isos and system shares are all hanging off /mnt/user and should be moved to cache.

I'll check where there is data and see where it's current (e.g., system share is recent on /mnt/user and empty on cache).

Stop the VMs and Dockers.

Copy the most recent data from system, appdata, domains and isos shares to cache in the correct subdirectory on cache.

Go into VM Manager and change the default VM and isos paths to cache.

Go into the share settings for system, appdata, domains and isos share settings, make sure all have cache as primary and array as secondary, and mover action is set from cache -> array. (Or do I set secondary storage as none? And if I do that, how do I back all these shares up in case the cache fails).

Restart VMs and Dockers.

Am I close?

3 hours ago, StevieGee said:

You're saying appdata, domains, isos and system shares are all hanging off /mnt/user and should be moved to cache.

cache is part of user shares. So anything on cache is in /mnt/user.

appdata, domains are all on cache so they're OK.

isos is all on disk2, but if you don't leave the iso mounted after you install a VM it won't have open files. Up to you whether you want to get those off the array. If you are unsure, move them to cache.

4 hours ago, StevieGee said:

system share is recent on /mnt/user and empty on cache

You need to quit thinking of /mnt/user and cache as separate things, cache is part of /mnt/user. /mnt/user includes all array data disks, and all pools, cache is a pool.

system has folders/files on cache and disk1 and disk2. It needs to be all on cache.

4 hours ago, StevieGee said:

and mover action is set from cache -> array

You have the arrow pointing the wrong way. That is going to move to the array.

There is no need to change any path to cache, cache is included in /mnt/user as explained above.

4 hours ago, StevieGee said:

back all these shares up in case the cache fails

You need to backup your appdata and VMs. There are plugins for that.

4 hours ago, StevieGee said:

Stop the VMs and Dockers.

Then move things as needed. Mover will do this for you if you make system (and isos if you want) to

Primary:cache; Secondary:array; Mover action:array->cache

But mover won't overwrite files. Shouldn't be a problem if system share on cache is indeed empty as you say.

Before restarting, check that things are moved where they belong. There are several ways to do that, but the easiest to explain is to just examine cache and disk1 and disk2 using the built-in File Manager.

4 hours ago, StevieGee said:

Restart VMs and Dockers.

Just now, trurl said:

You need to quit thinking of /mnt/user and cache as separate things, cache is part of /mnt/user. /mnt/user includes all array data disks, and all pools, cache is a pool.

You should never try to copy/move between user shares and array/pools. Linux doesn't know that user shares are just another view of array/pools, and will allow you to specify the same files as both source and destination. So, it will try to overwrite what it is trying to read. It creates a new empty file at the destination, then the source is that same empty file.

Built-in File Manager will not let you make that mistake. Command line, Krusader docker, mc (Midnight Commander) , sharing disks/pools along with user shares on the network, and many other things will let you make that mistake.

Trurl,

Well, it looks to me like disk2 is empty (attached)

And that appdata, domains, isos and system are all located on cache (attached)

And that your patience is astounding.

Thank you so much for your help, again!

Post new diagnostics.

Attached.

Oh, and another miracle, the dockers all work and appdata backup ended successfully.

smg-nas-diagnostics-20260303-1626.zip

Looks good!

You have a few .cfg files for shares that no longer exist. Use the CLEAN UP button on the User Shares page.

Check all your user shares to make sure they have reasonable settings for Minimum Free.

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/shares/#minimum-free-space

You also need to set Minimum Free for cache.

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/cache-pools/#minimum-free-space-for-a-cache-pool