Parity disabled with read errors during array shrinking

[shaybraham]

I was in the process of shrinking my array following the "Clear Drive then Remove Drive" method. I had manually removed everything from the disk and had kicked off the clear-drive script... and forgotten about it for a few days (so I didn't do steps 10-17 from the instructions about creating the new config and retaining the current configuration and removing the drive). Then I got some alerts about some read errors and the parity drive is now disabled.

I stopped the array and ran the extended smart test on the parity drive, tried rebooting (hopefully I didn't shoot myself in the foot there) but I'm too nervous to do anything with the array configuration. I've attached my smart test and my diagnostics. 

What should I do to get back to working order?

Edit: I failed to clarify that disk3 that was being removed is now reporting as "unmountable", which I think is because it was wiped clean. The diagnostics show the error when trying to mount that disk into the array. My concern is with the combination of the disabled parity _and_ the unmountable disk3 and how that might impact an attempt to rebuild parity or something.

diego-smart-20230328-1203.zip diego-diagnostics-20230328-1206.zip

Edited March 29, 2023 by shaybraham
Clarifying the issue

[JorgeB]

Disk was already disable at last boot so we can't see what happened, but it looks healthy, so most likely a power/connection problem, check/replace cables or swap slots and re-sync.

[shaybraham]

I tried reseating all the cables and swapping slots. What do I need to do to "re-sync"? 

I failed to mention that one of the reasons I'm concerned with doing anything to the array configuration to rebuild parity is because that disk3 that I was removing is now showing as unmountable (you can see that in the diagnostics), I think because the disk has been wiped so there's no filesystem or anything. I'm concerned that trying to "rebuild" parity with that disk still part of the array configuration but being unmountable is going to bork the parity rebuild.

Can I finish removing the disk _and_ rebuild the parity, or is there something else I should do like reformat disk3 but keep it in the array to rebuild parity?

(I'll add a note to the original post about the disk3 unmountable issue for future readers)

[JorgeB]

42 minutes ago, shaybraham said:

What do I need to do to "re-sync"? 

https://wiki.unraid.net/Manual/Storage_Management#Rebuilding_a_drive_onto_itself

 

42 minutes ago, shaybraham said:

I'm concerned that trying to "rebuild" parity with that disk still part of the array configuration but being unmountable is going to bork the parity rebuild.

If you are going to remove that disk just remove it now, and instead of the above do a new config without it (Tools -> New config) then start array to begin parity sync.

[shaybraham]

Ok, so tools > new config > preserve current assignments > all > yes I want to do this > apply/done. The warning on this page had me worried: 

Quote

DO NOT USE THIS UTILITY THINKING IT WILL REBUILD A FAILED DRIVE - it will have the opposite effect of making it impossible to rebuild an existing failed drive - you have been warned!

Then on main page, remove disk3 from array >
At this point do I check the "parity is already valid" box as described in Shrink array - Unraid | Docs step 14?

Then start array and manually start a parity check?

 

[JorgeB]

Parity was disabled so likely won't be 100% valid, but assuming it's mostly in sync you can check it then immediately run a correcting check.

[shaybraham]

Parity check completed with a ton of errors.... Should I be concerned about the health of my parity drive?

The smart report I attached to the first post didn't seem to indicate anything bad... but this sounds a bit worrisome:
 

Last check completed on Thu 30 Mar 2023 03:36:21 AM MDT (today)
 Duration: 18 hours, 5 minutes, 48 seconds. Average speed: 153.5 MB/s
 Finding 1678945 errors

 

[JorgeB]

Those are sync errors and expected:

 

On 3/29/2023 at 4:14 PM, JorgeB said:

Parity was disabled so likely won't be 100% valid

 

[shaybraham]

Cool then. Thanks for your help @JorgeB!