Replacing a failing drive, but TrueNAS Core won't allow me to use the new drive

TrueNAS General
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I started having a drive fail on me a while ago. Here’s my initial post:

Unrecoverable Error - Please Help! - TrueNAS General - TrueNAS Community Forums

When I got a repalcement drive - same size, brand, model number - I could not get the TrueNAS box to allow me to use it to replace the failing drive in the system. I put it in and instead of recognizing the drive as a replacement for the ada2 drive in my system, it identified as /dev/gptid/[serial number]. However, I could not add it to the pool or replace the ada2 drive. Even following the instructions would not work.

I see from searching that /dev/gptid is not uncommon, although I can’t determine why it’s not showing up as ada2. This is my first drive replacement. Is there something fundamental I am missing? Or is there something I need to do with the new drive to make it ready as the new ada2 drive that is not spelled out in the FAQs?

Thanks in advance for the help.

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It’s supposed to use the GPTID (for the partition), not the kernel sequential naming (ada1, ada2, etc).

The GUI shows “ada2”, but in reality, the pool’s vdev(s) is constructed with the GPTID with TrueNAS Core.

What steps did you try in the GUI to replace the failing disk?

I also highly recommend you create a checkpoint now, which you can delete later after everything looks fine:

zpool checkpoint poolname
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Thanks for your comments. I was able to figure out how to get the new drive installed and resilvered. I am up and running at full health.

Quick follow up question. I am sending the drive back to the manufacturer under a RMA. I looked for instructions on how to wipe the drive before I sent it back in and found these:

Wiping a Disk | TrueNAS Documentation Hub

But this seems to indicate that I have to put the original failing drive back into the NAS to use the system. Is there a way to do this with the existing two drive set up? Can I take the new resilvered drive, take it off line, put the original failing drive in and then wipe if before I send it back? Or is there a better/safer way to do this?

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Do you have a spare PC? If so, you can install the drive (temporarily) in another computer, boot into a Linux live ISO, and then run a pass of zeroes on the entire drive using dd or ddrescue.

I would strongly advise that you physically unplug any other drives, so as to not accidentally wipe the wrong one.

The above can also be done on your TrueNAS server, but you would instead boot into a Linux live ISO (USB stick) with the other harddrives unplugged.

You don’t need to be running TrueNAS with imported pools in order to wipe a single drive.

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