Complete moron (me) would like to know if this is right

[Oddwunn]

I have been replacing 3TB disks in my array with larger 4TB disks. The first 2 went in just fine (one at a time, of course), and the array properly rebuilt the new disks with the data from the old disks. When I got to the 3rd replacement (disk 21), the data rebuild was horrendously slow with the WebGUI reporting that the rebuild would take 28 days to complete. At that point I tried, while the rebuild  was in progress, to copy the data from disk 21 to disk 15 which was completely empty. I did this by using Putty and running MC to do the disk copy internally in the server. That internal transfer was not working, so I aborted the MC copy to disk 15. When I did that, then suddenly the data rebuild, for no apparent reason, picked up speed tremendously and reported that the data rebuild would be complete in 9 hours (normally this rebuild takes 18 hours on this server). 

 

When the rebuild was complete, I discovered that disk 15 no longer was mountable, so I stopped the array, restarted it and told it to format any unmountable drives. Disk 15 was then formatted, was now mountable, and parity began rebuilding itself and I thought all was well .... until I tried reading disk 21, the disk that had been rebuilt with the weird slow/fast rebuild time. As it turns out, disk 21 was completely trashed with most of the files gone and  and a directory that I can't even enter.

 

So now I am trying to save disk 21 by replacing the trashed 4tb drive with the original 3 tb drive, which should be fine. Please let me know if I am planning this correctly:

 

1. Stop the array

2. Unassign the parity drive

3. Replace the trashed 4TB drive with the original 3 TB drive.

4. Start the array to check that the files are ok on that drive.

5. Stop the array again.

6. Hit the "new config" button and tell it to keep current assignments (I have never tried a "new config", so this is where I want to make sure that I don't screw up)

7. Reassign the parity drive as per before.

8. Start the array once again and parity should be reuilt from scratch, right?

 

Is this the correct way to fix my problem, or is there a more efficient or otherwise better way to get the job done? 

[JorgeB]

Please post the diagnostics: Tools -> Diagnostics

[Oddwunn]

Oops...sorry. Here it is.

tower2-diagnostics-20210219-0733.zip

[JorgeB]

Syslog is missing a lot of time, can't see the rebuild, disk21 needs a filesystem check, you can try that before using the old disk, but without seeing what happened with the rebuild probably best to use the old disk as there might be data corruption.

 

12 hours ago, Oddwunn said:

3. Replace the trashed 4TB drive with the original 3 TB drive.

4. Start the array to check that the files are ok on that drive.

You can't do that without doing a new config, if you just want to check the data in the old disk you can do that with UD, make sure the array is stopped first, you can then do the new config and re-sync parity with the old disk.

[Oddwunn]

"Syslog is missing a lot of time, can't see the rebuild, disk21 needs a filesystem check, you can try that before using the old disk, but without seeing what happened with the rebuild probably best to use the old disk as there might be data corruption."

 

I am pretty sure that the 4TB disk 21 was trashed (or maybe defective out of the box) during the rebuild, so I want to pull it out of the array. I just want to make sure that the 8 steps I outlined above are EXACTLY correct because if I am wrong, I might inadvertently rebuild the 3 TB disk with the bad parity information. 

 

Are steps 6, 7, and 8 precisely correct? That is, when I reassign the parity drive and then start the array, will parity be newly recreated rather than rebuilding disk 21 with the old, bad parity?

 

Thank you for your help!

[JorgeB]

54 minutes ago, Oddwunn said:

Are steps 6, 7, and 8 precisely correct?

Like mentioned the old disk can only be re-assigned after the new config, rest of the steps are correct.

[Oddwunn]

Ok, gotcha....many thanks again!