I just wanted to reply to say that I'm sorry I didn't figure it out before asking my previous question, so please ignore it.  I have copied all of the data from the backup image onto Disk 4 (MD4) and have tested all of the files on it with no issues.  I restored the "lost+found" file after determining what it was after it was recovered in my reiserfsck of the image I had previously run.  Disk 4 (MD4) is finally now the way it was when I browse it in Explorer.

 

The original 2TB drive now needs to be added back to the server, so I just wanted to see what the next steps are exactly.  Should I just reassign the physical drive to Disk 4 (MD4) in the UnRAID GUI after first boot up upon re-installation of the drive?

 

I seriously can't thank you enough, and I am glad that now in the future if I ever have to do something like this again, I'll know exactly what I need to do!  Thanks again!

Attach a screenshot of unRAID Main.

Please see the attached screenshot of my UnRAID main menu.  Let me know if you need anything else!  Thank you so much for taking a look at this for me.

Assign and rebuild disk 4.

Assign and rebuild disk 4.

The rebuild of Disk 4 completed in just under 8 hours, and everything appears to be good!  I tested files and everything seems to be okay.  The drive has a nice green ball next to it and it's accessible within UnRAID GUI and Windows Explorer.  It shows a large number of writes to Disk 4 in the GUI as well, so it appears to have rebuilt completely.

 

Would my next and hopefully final step be just to run a parity check?

 

Thank you so much for all you've done.  As I look back at all the steps, this seems like something I should have been able to figure out on my own, but I always have a fear of the unfamiliar when it comes to potentially losing data.

Yes.

Yes.

Great!  Thanks again!

 

Just so I have a full understanding, my last and final question (I promise!) is whether or not I should be doing a correcting or non-correcting parity check. Assuming since parity was botched, that means I need to do a correcting one.  I only ask as I know this process takes a long time and any less wear I can put on the drives by doing the right option first is a good thing.

 

Thank you for being so patient with me as I know I should have understood more about the operations of UnRAID before jumping into it, even though I've had no problems for several years before this.

There's some debate about this.

As a 'boots and suspenders' type, I run a non-correcting and if there are errors decide what to do.

(and that's  always been to 'correct').

For that reason, others advocate just going straight to the correcting parity check.

 

I believe there are RARE cases when parity correction is not appropriate. But very very very rare...hence the idea of going ahead and running a correcting parity check. 

 

Sorry..I realize that's not much help!

 

If in doubt - do a non-correcting check. But if your parity is out of sync with your disk contents, it will be immediately apparent as parity sync errors will skyrocket immediately. My sense is after it runs for a minute, if you have zero parity errors, you can stop it and restart in correcting mode. Correcting mode will do nothing more than update parity. Unless you suspect one of your drives is failing and that parity is likely more reliable than the data disk, that's what I would do.

 

But normally, correcting or non-correcting, there will be zero parity errors. If you start to see one every once in a while, test your memory. If you have a few after a power outage or server crash, that is normal. Just let it correct them.

Thank you everyone!  I ended up doing as bjp999 suggested, which was run a non-correcting parity check for a few minutes to see if there were any errors, which there weren't.  I stopped that check and did a correcting parity check, and it came back with 0 errors!  Sounds to me like I'm back in business

 

Thank you to everyone who helped me get through this!  In retrospect it seems like it was something I should have been able to figure out without having to bother everyone, but now I will know for next time in case this ever does happen again!