After changing hardware my btrfs pool with 1 drive will not mount.

I noticed the output of "btrfs fi show" shows a 2 drive pool with different drive names then what the same drive is called on the new system

i woudl attach diagnostics but the server is not available on the network for some unrelated reason

Sorry for the grainy picture but this is what I get when running a btrfs rescue

i retrieved diagnotics by command and copy from the USb stick

marnas-safemode-diagnostics-20251225-0244.zip

Pleas post the output from btrfs fi show

Why are you not accessing the GUI via another PC/device; it looks like you are taking photos instead of screenshots.

That doesn't look very good, but 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 number of slots

assign those two pool device (nvme1n1 and nvme2n1), leave the filesystem set to auto

start the array and poist new diags

i had a long morning/night because there were network issues i was having and my Unifi controller was on the BTRFS pool.😥

I fixed that so now i have full access to it without getto screenshots

marnas-diagnostics-20251225-1421.zip

Dec 25 14:21:08 MarNAS kernel: BTRFS warning (device nvme1n1p1): devid 1 uuid 4becd2c2-6d8d-4c9b-84ff-94b33b1a7548 is missing

It's reporting a missing device despite devid 1 being on the btrfs fi show output, so there' some confusion going on.

Since devid 2 is listed as empty on the previous output, try this:

Stop the array

type echo 1 > /sys/block/nvme1n1/device/device/remove , this will drop that device offline until a reboot

try reimporting the pool again but with just nvme2n1

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 remaining pool device (nvme2n1), leave the filesystem set to auto

start the array and post new diags

That worked like a charm! Thank You JorgeB!

Great, note that if you reboot and try starting the array without wiping the other device first, you will likely see the same issue.