Recently had an odd little thing happen with my unRAID server (v6.12.3) and was wondering if anyone could shed some light on it.

I recently upgraded my parity drive. For context, I've had zero issues with unRAID save for a hard drive that started to crap out a few months ago. No issues with the server itself. I was upgrading from an 8TB parity to a 10TB parity. I've upgraded my parity maybe a half dozen times, and the time between each upgrade is usually years, so I do it slightly differently each time.

I googled how to do it to be sure and found a YouTube video of a guy talking about how to do it and it seemed even easier than I remember. He stopped the array, set parity to "no device," put it in maintenance mode, start the array, stop array, physically swap parity drive. I'm paranoid, so at this point, I did a full shutdown of my server to swap the 8TB drive for the 10TB drive even though I've got hot-swap capabilities. Restarted the server... nothing. I don't have a monitor connected to it constantly, so I couldn't see what was actually happening; instead, I just wait until the web portal is available to know things went fine. After an inordinate amount of time, I went to check the server -- motherboard was giving no error codes on its display, showing only FF for fully functional. Odd. I forced a restart, same thing... except this time the error code was AE which meant there was a problem finding a boot device. The USB stick hadn't moved from its port, and the physical server hadn't moved... just a drive swap. I threw the 8TB drive back in and booted it up... no issues. At this point, I figured I could probably hot swap the drives, so I did even though I figured this portended trouble. Went and swapped the 8TB for the 10TB, refreshed the portal, added the 10TB into the parity slot and started the array, (re)built parity, no issues.

When parity finished, I tried a complete shut down just to see, and as I suspected, same issue: won't boot. Hooked up the monitor to eventually get the "unable to enumerate USB device" error. Found another forum post about this and saw there can be issues with USB3 ports, and all I've got on my mobo is USB3. Luckily -- I guess -- my case is old enough that it has a USB2 on the front panel, so I threw the USB in there and no issues, booted right up.

So my issue is "fixed" (even though I'd rather have the USB on the back of the case, where it can't get accidentally knocked as easily).

I just wanted to make a post here to see if anyone could shed some light on what exactly happened, and why.

Thanks in advance!

Edit to add: the USB stick is virtually brand new (purchased July 2023, upon further review). Upgraded to a Samsung BAR Plus, presumably after checking whether it was good with unRAID and reliable. Swapped the USBs shortly after purchase and have had zero issues since then.

Edited March 31Mar 31 by CasanovaFly

That looks like a BIOS issue; possibly connecting the new disk changed the BIOS order or device limit, if you left the old one connected.

12 minutes ago, JorgeB said:

That looks like a BIOS issue; possibly connecting the new disk changed the BIOS order or device limit, if you left the old one connected.

I did not leave the old drive connected; hot swapped it out. I did some preliminary checking in the BIOS at the time and couldn't find anything that seemed like it would have explicitly fixed the issue, and all the BIOS boot options available to me were the various hard drives. I also have all the hard drives connected to a few SAS2LP RAID controllers.

I'm not doubting your logic, I'm just trying to wrap my head around this. After all, when I just put the 8TB drive back, without changing a thing, it was fine. And, if anything, I removed a drive from the array (and the server) a few months ago so if anything I'm down a drive since I switched the USB out.

On the surface, it seems like there were an issue jumping from an 8TB drive to a 10TB drive, as that's the only thing that really changed.

38 minutes ago, CasanovaFly said:

On the surface, it seems like there were an issue jumping from an 8TB drive to a 10TB drive

Don't see how just that can be the problem.

56 minutes ago, JorgeB said:

Don't see how just that can be the problem.

I don't, either, but that's the only thing that really jumps out at me. Especially because I could just swap the drives back and the issue would resolve itself. You would think -- or at least I would -- that if adding this 10TB drive (to an existing slot) changed the BIOS boot order, it would stay changed even if I added the 8TB back.

The only thing that throws up a flag for me is that I believe Windows used to have an issue back in the day booting from drives larger than a certain size. I think it was 2TB and then it moved to GPT style or something and there were early issues booting from that. But honestly I have no idea at all. I'm about to go ferret around in the BIOS and see if anything jumps out.

Edit: upon perusing the BIOS, there's nothing that jumps out. With the USB stick in the front panel (USB2), I can see all the possible boot devices (well, 7-8 of the drives plus the USB) and reorder them and choose a specific boot device. When I put the USB stick in the back (USB3), it disappears completely from the list of bootable devices.

Edited March 31Mar 31 by CasanovaFly
Checked the BIOS