I have a drive failed that was labeled as sdu. I had to reboot the machine and when everything came back up, things look off. zpool status looks like this:

 

you see that sdu is reslivering and sdp is offline. but looking at the UI:

 

you can see that sdu is there and fine, and sdy is not there. looking a bit lower, and I see:

 

This is the failed drive... I think. but looking in the enclosure, it is being accessed a lot. so I have no idea which drive to pull. prior to the reboot this is the serial that failed. (ZL22Q517) 

 

can someone educate me on what is going on?

backup-diagnostics-20231204-1203.zip

zfs pool devices should be assigned exactly in the same order as zpool status shows, or it can cause issues with device replacement, but suggest bringing the pool to a healthy status manually first, then re-import with the correct order.

 

 

gotcha!

 

my question is how do I find the bad drive now? 

now sdu in zpool status is "Removed"

zpool replace -f -o ashift=12 pool_name 11973730308935320399 /dev/sdX1

 

Just an example, you need to use the correct identifier for the offlined device, as shown on zpool status, also need to replace X with the correct new disk identifier, if the replacement disk is not formatted you can do it with UD first.