woothie

Turns out it (probably) was power, yeah. Reseated the Molex cables going into the backplane and added some extra force when putting them back in, rebuilt just fine. Thanks a bunch guys! What in the diags pointed you to cable/power as the likely culprit?

Noted, I'll do another check with the wiring. They're all connected via a backplane so the only actual wiring is power to the backplane via Molex and the data cables to the H200. Would be odd if it were power though, surely we'd see issues with other disks on the same line, at the very least. That's disks 5, 7, 9 and 11.

Well darn, it failed. I checked in on it after a few hours, turns out it had gone on pause after about 2 percent without me realizing. Seems there's a problem with disk 5, but I can't quite figure out exactly what. I can see in the disk info screen there are io issues, but exactly what is beyond my understanding. Any ideas? Attached is diagnostics. Worst comes to worst I have another 2tb precleared disk on standby thedatadungeon-diagnostics-20250330-1902.zip

That seems to be the way to go, yes! I now have disk 5 and 7 rebuilding, I'll update with how it goes. Thanks for the help so far!

Gotcha, thanks for the very quick response. I've reseated cables and the H200's, seems like I still get the same status. Disk 5 is still red, disk 7 seems fine but since it's new it's now rebuilding. I could try to replace disk 7 with the original disk 7 which (probably) has all the data on it still, but I assume that will just leave me with two reds as it did fail to begin with. As I started the array it once again started rebuilding disk 7. See attached diagnostics. I'll leave the array rebuild until advised otherwise. thedatadungeon-diagnostics-20250330-1229.zip

Hello! I had a disk go red marked disabled, I'm not 100% sure if this was after a reboot or by itself during operation. Either way, I span the array down and replaced the disk by pulling it out, putting in a pre-cleared disk of the same capacity (and make) and assigning it to the same disk slot out of an abundance of caution (logs seemed to hint at a filesystem error, but I decided not to take any chances), and started up the array for data rebuild. This made a SECOND disk also get disabled, which prompted me to make this post. I have two parity disks and 11 data disks total. Hardware is a supermicro x9dri-ln4+ motherboard running a single intel xeon e5-2697v3 (the second socket got some traces destroyed by yours truly when attempting to mount a third party cooler with too long screws, whoops). I also have a GTX 1070 attached for accelerating GPU workloads, spesifically ML stuff on Immich. So all three PCIe slots for CPU 1 are populated. See diagnostics data attached. All disks apart from my two SSD cache drives are attached to the system via a SATA/SAS backplane, again via two DELL H200 in IT-mode. Disks of odd and even numbers are attached to separate h200's respectively (i.e. all odd numbers are on one H200, and all even numbers on another). I say this because disks 5, 7 and 9 have had issues, although disks 1, 3 and 11 are fine (for now). I also had disk 9 throw some errors during the initial rebuild (so at one point I had 3 disks be in varying degrees of not-okay), but after a reboot this went away. Seems this was due to SMART throwing Unraid off with a change in reallocated sectors, although I personally think this is within acceptable limits. Most of the harddrives are old DELL Constellation 2TB drives, about 8 years old or more, bought used. I marked disk 9 and 5 SMART-errors as Acknowledged. I figure as long as reallocated sectors is not climbing fast or consistently, the disk is safe to use. This is the state of my Main-page as of right now. Disk 7 is what prompted this change in the first place, it seemed to be in much the same state as disk 5 is now. I still have the original disk 7, the one currently in the array is the pre-cleared backup in need of data rebuild. I have cancelled the data rebuild for now. What should my next steps be? I'm keeping the array off/in maintenance mode until I'm sure of what to do next. I do have another 2TB pre-cleared backup drive, but I figured replacing two disks at the same time is either inadvisable or not supported, in the same vein where you're not allowed to i.e. remove AND add a drive simultaneously to the array. EDIT: I've also attached the diagnostics from during the data rebuild, as I rebooted after cancelling it the first time. As mentioned above, this was because I got scary read errors from Disk 9, which thankfully seemed to be transient or due to Unraid marking the disk as not safe because of reallocated sectors changing. The current diagnostics is the one timestamped 1139, and the one which includes the data rebuild is timestamped 1100. thedatadungeon-diagnostics-20250330-1139.zip thedatadungeon-diagnostics-20250330-1100.zip