Hi, I'm having some trouble with my btrfs cache pool.  It's comprised of 3x 1tb SSD's.  I had one drive that was failing and kept locking up unraid forcing hard resets, so I was planning on replacing it.  I shut down my array, removed that drive from the cache assigned devices and started the array again, but my cache pool stopped working (Wrong or no file system), I assumed it would continue working on 2 instead of 3 drives (I'm only using 600gb) but that doesn't seem like it's the case.  I stopped the array again, and added the failing drive back as an assigned drive to see if I could recover anything from the pool.  That gives me an error 'cache - invalid expansion'.  

 

I do have my app data backed up, so it's not a huge deal if I can't recover anything (I'll lose my vms though).  So I tried to remove the pool, to recreate it but I'm unable to do that either, I can't 'un-assign' the pool devices, only set it to no device which doesn't let me reduce the slots to 0, or enable the delete pool option. 

 

I think my mistake was trying to remove the failing drive from the pool instead before replacing it with a new drive (which gets delivered tomorrow).  And now I'm kind of stumped, I can't seem to start the array to begin recovering my dockers and vms, I can't fix the pool by re-assigning the 3 drives, and I can't delete the pool and start fresh.
Thanks for any help or advice

-hd

pantainos-diagnostics-20250322-1257.zip

Edited March 22, 20251 yr by Happydish

Following up on this, made a new config, didn't setup a cache pool.  Currently doing a parity sync on the array, and I'll setup a new cache with new ssds when they get here tomorrow

If you still want to try and recover the pool, connect all 3 devices (but don't assign them for now) and post the output from

 

btrfs fi show