Multiple Failed Drives - Need Help


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Hello all. I'm in a bind at the moment and would very much appreciate some help/advice with this situation.

I had my 1TB (Disk 4) drive randomly mark itself as failed. I turned off the server and attempted to replace the drive. When I turned it back on again, a second drive (2 TB - Disk 1) began to fail, before Disk 4 could be rebuilt. Unfortunately I only have a single parity drive. I have since run a short self-test on Disk 4 and it passed. This drive only has ~8GB of stored data that I don't really care about. Disk 1 on the other hand has 1.5TB of data that I do very much care about.

I purchased another 2TB drive in the hopes that I would be able to re-assign my drives to the array, mark Disk 4 as okay (I believe it should be able to be read from but I'm not positive), and rebuild Disk 1 from parity. When I attempted to do this, I was not able to start the array as it of course is saying that too many drives are wrong/missing/in error.

Is there a way that I can assign Disk 4 to the original drive, mark it as okay, replace Disk 1 with the new drive, and then rebuild Disk 1 from parity? If so, how would I go about this?

I read that using the New Config tool may be able to help me accomplish this, but when I navigated to that page it explicitly stated that it would invalidate my parity and force it to be rebuilt, which of course is exactly what I don't want to happen at the moment.

I'm hoping to avoid having to send Disk 1 to a data recovery service if possible. 

Any assistance would be very greatly appreciated. Thank you!

 

Attached is my diagnostics file: unraid-diagnostics-20201124-1341.zip

Edited by anunraiduser
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You can try this:

 


-Tools -> New Config -> Retain current configuration: All -> Apply
-Check all assignments and assign any missing disk(s) if needed, including the new disk you want to rebuild, replacement disk should be same size or larger than the old one
-Check both "parity is already valid" and "maintenance mode" and start the array
-Stop array
-Unassign the disk you want to rebuild
-Start array (in normal mode now), ideally the emulated disk 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 the disk to rebuild and start array to begin.

  • Thanks 1
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Okay, so the disk was marked as unmountable (no filesystem) but I decided to chance it and run the rebuild anyway. The rebuild took about 5 hours and there were 188 errors during this process, so just from that alone there's likely going to be some data corruption.

When I finished the rebuild, the disk was still marked as unmountable, so I went into the terminal after starting in maintenance mode and ran an xfs_repair /dev/md1 which found some issues and then completed. I then started up the array again and was then able to access the filesystem. I've only done a quick spot check so far, but my files seem to be intact! I'm sure there will likely be some corruption due to the 188 errors if nothing else, but recovering any data at all at this point is extremely good news!

I'm going to keep the old drive on hand in case I run into any absolutely critical files that are corrupted, in case I need to have those restored.

In the meantime, my plan is to move all the data off of disks 4 & 5 (~9gb of data) and shrink the array, removing the 1TB and 500GB drives that are essentially empty anyway, reducing the possible points of failure.

Then my plan is to get some NAS specific (6TB+ IronWolfs or Red Pros) drives during Black Friday sales to bring my array up to double parity, replacing and retiring the current parity drive (I broke the plastic part of the SATA connector off by accident during my initial investigation as well and am amazed it's still working quite frankly), and then replacing the newly rebuilt 2TB drive with another 6TB NAS drive as the current one uses SMR, then I'll keep it as a backup.

I was essentially prepared for the worst but I'm ecstatic to see that any of my data at all is safe. With any luck, my truly important files will be fine as a large portion of the drive is populated with replaceable media files and disk image backups of other PCs on the network.

Thanks again @JorgeB, your help was invaluable!

Edited by anunraiduser
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