kolepard

Most of my last message disappeared, an only the diagnostics appeared; I'm not sure why.

That Seagate drive is will appear "spun up" for a while after a power cycle, no matter how I attach it, which I think is the major problem. The last set of diagnostics was obtained while it was "spun up" (i.e., green dot). What I did was run

btrfs dev remove missing /mnt/cache

It reported no device was missing, which was true, so I did this:

Ran a balance operation and let it finish.
Stopped array
Set the problematic drive, sdj, to unassigned
Checked "I Want to Do This"
Restarted the array
Let the BTRFS Operation complete, which showed a cache pool of 3 devices (Huzzah! Progress!)
Stopped the array again
Removed the second SSD
Again checked "I Want to Do this"
Restarted array
Let the BTRFS operation complete again


This has left me with a pool 2 devices of the 2 NVMe drives on the PCIe riser card. Fortunately I was able to complete the first 5 steps before the troublesome SSD dropped off and reported "spun down". I'm not sure what I would have needed to do if the troublesome drive "spun down" before I could complete those steps.

I presume these remaining 2 drives are mirrored, correct?

Is there a better way for me to set this up so I avoid this problem in the future? Or was this just bad luck?

Thank you again for your help.

Kevin