I just had this error pop up today, Device 1 (sdd) on Cache pool (Edit: Raid0 it's RAID1, copy, I mistyped that) is not working. It was initially throwing Errors with every write, so I shut down the server and changed the SATA cable. Now I restarted and it has no reads/writes.

Uploaded diagnostics. Is that sdd drive (HFS500) toast? What else can I try?

Thanks in advance!

untower-diagnostics-20261010-2207.zip

Edited yesterday at 05:14 AM1 day by mattz
mistyped raid0, it was a raid1 / full copy setup

The first device (the HFS500) failed. SMART reports it as failing, and it also lost its partition, so it's no longer part of the pool. The pool is running degraded using only the ADATA NVMe. All data is still there, because with raid1 the NVMe has a full copy.

Important: the ADATA SMART also shows it's failing. It's worn out (140% of its rated life used, critical warning set). Before anything else, back up anything important from the pool, for example to the array.

Then you can fix the pool. With the array running, type:

btrfs balance start -f -dconvert=single,soft -mconvert=dup,soft /mnt/cache

when that's done type:

btrfs device remove missing /mnt/cache

Then stop the array and re-import the pool with the remaining device:

- on Main click on the first device for that pool and then "remove pool"

- back on Main, create a new pool with the same name and 1 slot

- assign the ADATA NVMe, leave the filesystem set to auto

- start the array to import the pool

The pool should be imported as a single-device pool. Don't re-use the HFS500. To get redundancy back, stop the array, change the slots to 2 and add a new device to create a mirror. Since the ADATA is also worn out, plan to replace it soon too.

Thank you, @JorgeB . Good points. Those drives are ancient, in SSD terms. I will get a new drive and get back with my results.

9 hours ago, JorgeB said:

Then you can fix the pool. With the array running, type:

btrfs balance start -f -dconvert=single,soft -mconvert=dup,soft /mnt/cache

when that's done type:

btrfs device remove missing /mnt/cache

How long will it take for the first command to run?? I left it for over 30-minutes, and it just sat at the command line. I finally canceled it with Ctr+C and the command line recovered, but I didn't see any changes.

It should take a few minutes; 30 seems a lot. Please post new diags assuming you didn't yet reboot.