A couple of days ago, my unraid server reported that one of my disks had been disabled. The disk appeared to be healthy so I followed the instructions for rebuilding the drive here: 

 

Manual/Storage Management - Unraid | Docs

 

This looked to be working as expected but when it finished all it appeared to have done was performed a parity check and it informed me that there were a very large number of errors. I assumed, possibly foolishly, that I had somehow just got something wrong in the process and I followed the rebuild instructions again, but after it started, there was another disk which was flagged as "unmountable" so I now have two disabled disks. 

 

At this point I realised that I was definitely in over my head and needed some support from people who actually know what they are doing, so I took down the array and made this post! 

 

tower-diagnostics-20220919-2211.zip

You are having issues with multiple apparently healthy disks, this suggests a power/controller/cable problem, do disks 3, 4 and 9 share anything in common, like a miniSAS cable or power splitter?

They share both a mini sas cable and a power splitter cable

I would start with replacing that, then you'll need to force enable disk4 to rebuild disk9, or re-enable both if nothing was written to disk9 after it got disabled.

I can replace the power splitter but I don't have another sas cable on hand. I should be able to hook those drives into the motherboard directly though so I guess I will do that too. How exactly do I go about force enabling disk 4?

Was anything written to disk9 after it got disabled?

not sure. Is there any way that I can tell other than starting up the array and checking when the last files were written to the disk?

 

You cannot check now since there are two invalid disks with single parity, so they cannot both be emulated, if you're not sure it's best to enable only disk4 and see if disk9 can be correctly emulated:

 

-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all disks are assigned, assign any missing disk(s) if needed
-IMPORTANT - Check both "parity is already valid" and "maintenance mode" and start the array (note that the GUI will still show that data on parity disk(s) will be overwritten, this is normal as it doesn't account for the checkbox, but it won't be as long as it's checked)
-Stop array
-Unassign disk9
-Start array (in normal mode now), ideally the emulated disk9 will now mount and contents look correct, if it doesn't you should run a filesystem check on the emulated disk
-If the emulated disk mounts and contents look correct stop the array
-Re-assign disk9 to rebuild and start array to begin.

 

 

I have kicked off the process as you suggested and it looks to be doing what it should be. I guess I will know in a couple of days as it is a 16tb drive!

 

Thanks for your help, I'll report back once it is (hopefully) fixed

OK, I assumed disk9 mounted?

yes it did.

I'm a bit  late replying but I just wanted to note that this worked perfectly and my server is back up and running again.

 

Thanks @JorgeB for all of your help.