Help, i just woke up and got the message that one of my Drives failed. That is during my routine parity Check. and now two of my other drives are climbing in sync errors. What do i do now?

Edited April 26Apr 26 by Jakobustrop

The Log is full of Disk 2 and 3 Read errrors. I feel liek the Parity sync should continue

No point in continuing the Parity Sync if you are getting read errors on the data drives.

I stopped the Parity Sync and checked all the Drives that dropped. They were all connected to the same controller. So pretty sure that is dead. I checked the smart data of the drives in a different system and they all check out fine. Is the correct step now to rebuild drive 1 onto itself? or do I take a different appraoch because of the last parity check that accumulated errors because of the lost connection to drive 2 and 3? Because theoretically i would assume the data on drive 1 is still good.

You should definitely not rush into rebuilding disk1 as parity may no longer be valid after getting all those read errors. As you say there is a good chance that the data on disk1 is actually all intact if it dropped offline due to a controller issue.

Have you tried a power off/reboot sequence to see if the disk controller is recognised OK?

You are likely to get better informed feedback if you attach your system’s diagnostics (with everything in the one zip file) to your next post in this thread. It is always a good idea when asking questions to supply your diagnostics so we can see details of your system, how you have things configured, and the current syslog.

I have powered off the system and swapped Mainboards to one with a known good Sata controller. I rebooted into Maintenance mode and all the drives show up fine. Also did a short smart test on drive 1 and that also came back without error, same with drive 2 and 3.

Sorry i forgot the Diagnostics. Should have also taken one earlier before the reboot. I was in kinda of a frenzy/panic waking up to the notifications and wanted to get it under control. I have now attached the diag from the current boot

jarvis-diagnostics-20260426-1054.zip

To see if the emulated disk is mounting, start the array in normal mode and post new diags

Alright here is the new Diag. I am able to see the contents of the emulated disc.

jarvis-diagnostics-20260426-1143.zip

As far a i can see I have two options right now:

1. Rebuild Disk 1 onto itself assuming the parity data for that drive is good. I assume the parity data for disk 2 and 3 will be bad because the parity sync continued while they threw errors.
2. Create a new Config and rebuild parity from there.So assuming the data on the disc is fine, assuming the Controller failed in a way that took down the drives and didn't destroy data already on there.

Or am I missing something?

The emulated disk is mounting. Assuming the contents look correct, we typically recommend a rebuild:

https://docs.unraid.net/unraid-os/using-unraid-to/manage-storage/array/replacing-disks-in-array/#re-enabling-a-disabled-disk-rebuilding-onto-itself

So I would follow those steps and then run a parity check to correct the faulty parity data for disks 2 and 3 right?

52 minutes ago, Jakobustrop said:

So I would follow those steps and then run a parity check to correct the faulty parity data for disks 2 and 3 right?

Parity is never held at an individual drive level but is always system wide. If the emulated drive is mounting OK and the expected files are showing then after a rebuild parity should be good as all drives plus parity drive are involved in a rebuild. If the expected files are not showing then a rebuild is probably not the best next step. After a rebuild it would not hurt, however, to run a parity check at that point although it is probably not needed as it should be correct.

Alright, I have the file integrity plugin installed. Would it be smart to let that verify the contents of the emulated disk 1 one to check if everything is in order before proceeding?

1 minute ago, Jakobustrop said:

Alright, I have the file integrity plugin installed. Would it be smart to let that verify the contents of the emulated disk 1 one to check if everything is in order before proceeding?

That plugin cannot check integrity of files added before the plugin was installed. It can be set automaticallygenerate checksums for new files, and can also create checksums for existing files based on their current contents.

Checked the Data on the emulated Disk 1 and it seemed to be all okay. Tested some media files and they all played back fine. Started the rebuild and it is half way done. Seems to be doing okay.

Just as an update the rebuild was successful and the server is back up and parity check didnt return errors.