Member disk list blank in replace disk dialog

I just had a disk fail:

I have a spare disk of the exact same model number that I want to replace it with:

I click the failed disk’s three dots menu in the Pool Status screen and select Replace to get the replacement dialog. The problem is when I select the Member Disk menu, my spare da5 disk is not available in the menu:

How can I get past this? Thanks in advance.

I am running TrueNAS-13.0-U6.2.

Further troubleshooting. I tried to see if I could make a single-disk pool from the intended replacement disk da5. I couldn’t do that because it does not appear in the available disks list:

I also looked to see if da5 might have had a forgotten pool on it, but the import function does not detect anything.

Wipe it?

Does your system support hot-swap? If not have you rebooted the system since inserting your replacement drive?

Yes, it supports hot swap. And the disk has been in there for a while, waiting for this exact purpose. But thanks for the suggestion. I will try rebooting when I get an opportunity anyway.

Good idea, but, hmm, wipe is missing.

I rebooted but the problem remains.

I rebooted with the replacement disk removed and then inserted it. Now something really strange has happened. The replacement disk shows on the Storage / Disks screen as already being part of the degraded pool. However, when I go to the pool status, it isn’t shown as part of the pool and it is not available as a disk to replace the failed disk with. Also, the replacement disk now shows the wipe action as available.

I tried to do the replacement straight away but got the error, “Disk is not clean, partitions were found.”

Then I wiped the replacement disk, which appears to have succeeded, but strangely the Storage / Disks screen still shows it as part of the degraded array. Finally, I tried replacing the failed disk with the now-wiped disk and it succeeded to start resilvering.

Strange stuff here. This should have taken me all of 5 minutes yesterday but ended up as a several hour affair.