Yesterday I discovered I had 2 drives (Disk 9 & 10) from my dual parity array be disabled by Unraid (Why is it always 2 at once? Can't it ever just be 1 at a time? Ugh) likely as a result of power issues I've yet to pin down. I had a drive (sdi) sitting in unassigned devices from the previous time this happened. After that incident I ran an extended self-test on the drive which it passed so I left it in the array in case of an emergency. So the first thing I attempted (after stopping Docker, I have no VMs) was to remove one of the disabled array drives (Disk 10) and replace it with the drive (sdi) sitting in Unassigned Devices. Once I started the array, the data-rebuild began, but after about 20m I noticed the projected completion time for this 8TB drive was sitting around 400 days . . . wut?

So I stopped the array and removed that drive from the array. I then decided decided to do a file system check on that drive. The test showed errors that I believe were something to the effect of "File System Corruption", so I had it run the fix and the next test showed no errors. I then attempted to put that Disk back in the array and start the data-rebuild but the result was the same: a super slow data-rebuild. As a result I pulled that drive from the array and put it back in Unassigned Devices. It now will not mount under Unassigned Devices, returning the error:

" . . . mount() failed: Structure needs cleaning. dmesg(1) may have more information after failed mount system call."

I ran a Short SMART Test which passed on that drive (sdi). I have added that SMART test to this post.

Returning to the issuing of restoring my array, I then decided to run a Short SMART Test on the other currently disabled disk (Disk 9) and attempt to rebuild it in place if it passed. The SMART test passed so I unsigned that disk (sdj), restarted the array with no disk assigned to Disk 9, then reassigned the same drive (sdj) to Disk 9 and started the array. Data-rebuild started, seemingly normally, after starting the array and showed an estimated rebuild time for the 8TB drive of about 14 hours. However, I checked back about 15m later and it again was showing something like a year to complete the data-rebuild. The data-rebuild has now been running for 2hs 20m and is showing an estimated rebuild time of 470 days, and I've seen it fluctuate between estimates of 350-550 days. What are the chances of this happening with 2 different drives?

Can anybody help me understand what is causing this? I tried to do some research, but I'm not finding anything yet. I will point out that all the drives currently in the system have been in the array during previous data and parity rebuilds. I have never had either of those take longer than 2 days and that was a result of replacing the parity drive with a 24TB drive. Any help would be greatly appreciated. I obviously can't wait a year and a half for this data-rebuild.

I did download and attach the system logs as well.

Many thanks

calculon-diagnostics-20250807-1842.zip calculon-smart-20250807-1800.zip

I did forget to mention, if it matters, that all attempts to do the data-rebuild have been in Maintenance Mode.

I did just find a post from someone with a similar issue commenting that rechecking all their physical drive connections fixed a the issue. Given I have had apparent power issues, this is a possibility. For what it's worth I did check all the connections already given the history, but I could try disconnecting and reconnecting them just in case. I don't want to make and changes or shut down the system right now in case someone is going offer advice, so I'm going to leave everything as is for now.

Issues with parity2, and it's not giving a valid SMART report, swap cables/slot with a different disk and post new diags.

As always, I appreciate your support Jorge. I just woke up and the data-build now estimates 17 hours to completion with all the read/writes synced at 100-110 MB/s so it seems to be working? I'm now thinking the safest bet is to let it complete? I do see Parity 2 has 100 errors displayed on the main page. Does this change your recommendation?

If it's going now, you can try and let it finish, but note that there could be some corruption on the rebuilt disks if there's data on the sectors that generated those read errors on parity2.

So I did finish the previously mentioned rebuild which finished with ~250 errors on Parity 2. I then attempted to do a data rebuild on Disk 10 which got to the mid-90s on completion before stopping. In the end there were 9198 errors on Parity 2 and 1024 on the disk I was attempting to rebuild (Disk 10). I have another drive I can replace Parity 2 with, but it's too large to put in the array. Would that be best next step?

I also looked at the data being emulated on Disk 10 and don't mind if I lose it. So I'm wondering if it's safer to rebuild the array altogether (new Parity) without Disk 10 if it's currently throwing lots of errors?

Edited August 12, 2025Aug 12 by beatmurph

Post new diags please.

Duh 🤦 sorry about that. Diagnostics are attached.calculon-diagnostics-20250812-0941.zip

Pariy2 is still not giving a valid SMART report, swap cables/slot with a different disk then post new diagnostics after array start.

OK, I moved Parity 2 to a new slot, started the array, and the diagnostics are attached.

calculon-diagnostics-20250812-1044.zip

SMART is showing issues for parity2, run an extended SMART test on it and post the results.

Well, that didn't take long 😬

Parity 2 extended SMART Report attached

calculon-smart-20250812-1029.zip

Test failed, disk needs to be replaced.

That's definitely how it looked to an amateur. Thank you for all your help. It was a cheap used drive, so I guess that's the chance I took. Hopefully the other 2 last a little longer. I think that one lasted like 2 months.