Drives became unreadable during parity check - now 2 are unmountable after reboot

[brambo23]

So I looked at the link you sent about rebuilding data onto itself.

 

The emulated data is missing the data that is on those drives. 

 

Should I copy the data off those drives in order to properly rebuild the array?  I assume if I add those drives back, since the emulated data is missing the data on those drives, it will blank out the data

[trurl]

2 hours ago, brambo23 said:

Can i just add them back to the disk they were originally assigned to?

That is exactly what I mean by "reassign".

 

It will rebuild them with the contents of the emulated disks, which were unmountable. 

[brambo23]

7 hours ago, trurl said:

That is exactly what I mean by "reassign".

 

It will rebuild them with the contents of the emulated disks, which were unmountable. 

so the second problem with that is i realized the emulated data is missing the data that's on those physical disks

 

what happens if i rebuild the array with that status?  will it rebuild the array as emulated then the data from the physical disks gets added? or the physical disks look more like the emulated disks and i lose that data anyway?

[trurl]

7 hours ago, trurl said:

It will rebuild them with the contents of the emulated disks, which were unmountable. 

That is all you will get from the rebuild. How could it "add" any data from the physical disks?

 

9 hours ago, brambo23 said:

I looked at the link you sent about rebuilding data onto itself.

I never did post a link about that in this thread.

  

10 hours ago, trurl said:

You will have to New Config them back into the array and rebuild parity.

 

https://docs.unraid.net/unraid-os/manual/storage-management/#reset-the-array-configuration

 

[brambo23]

3 minutes ago, trurl said:

I never did post a link about that in this thread.

You are correct, you didn't post a direct link, but it was in the contents of the one page you did link

https://docs.unraid.net/unraid-os/manual/storage-management/#rebuilding-a-drive-onto-itself

[trurl]

4 minutes ago, brambo23 said:

direct link

The direct link I posted is exactly what I intended. Lots of things in the contents.

[trurl]

There were actually 2 approaches to your problem

1. fix the filesystems on the emulated disks and rebuild.
2. fix the filesystems on the physical disks and New Config them back into the array.

I would have recommended 1, but since you had already started doing 2, I just went ahead with that.

 

It is still possible to do 1 if you want, and in some ways that would be more correct, Rebuild would recover any emulated writes, but since the filesystems were unmountable, it probably doesn't make much difference.

[trurl]

1 minute ago, trurl said:

it probably doesn't make much difference.

If you are happy with the physical contents of the disks, just go with that.

1 minute ago, trurl said:

New Config them back into the array.

 

[trurl]

Are there lost+found folders on the physical disks? 

[brambo23]

11 minutes ago, trurl said:

Are there lost+found folders on the physical disks? 

I do not see any lost+found folders on the physical disks in question

 

i tried re adding the drives and "rebuilding" the array, but when i started the array, the disk 8 and 9 were still listed as unmountable

[brambo23]

Judging by all the information I'm reading, it sounds like resetting the array configuration is the only way to make sure the data on the two drives remain intact

[trurl]

And you must allow it to rebuild parity, because parity is out-of-sync with the changes filesystem repair made to the physical disks.

 

[brambo23]

Just now, trurl said:

And you must allow it to rebuild parity, because parity is out-of-sync with the changes filesystem repair made to the physical disks.

 

So they will remain unmountable until the rebuild finishes?

[trurl]

1 hour ago, brambo23 said:

i tried re adding the drives and "rebuilding" the array

What exactly do you mean by this? If you starting rebuilding on the physical disks, you have already altered their contents and they are most likely unmountable now.

[trurl]

Just now, brambo23 said:

So they will remain unmountable until the rebuild finishes?

No, you have made them unmountable by trying to rebuild them. You will have to try to repair them again after rebuild finishes.

[trurl]

Rebuild makes the physical disks have the exact same contents as the emulated disks. That is all it can do.

10 hours ago, trurl said:

It will rebuild them with the contents of the emulated disks, which were unmountable. 

 

[trurl]

Do you have another copy of anything important and irreplaceable? Parity is not a substitute for backups. Plenty of ways to lose data besides failed disks, including user error.

[brambo23]

5 minutes ago, trurl said:

What exactly do you mean by this? If you starting rebuilding on the physical disks, you have already altered their contents and they are most likely unmountable now.

What I meant by is, I started the array and it immediately began the rebuild process.  Out of fear I cancelled the process, and the drives were not mountable until I did a file system check.  It repaired the issue again then I was able the mount the drives again.

 

It would appear the corruption is already logged in the parity

 

3 minutes ago, trurl said:

Do you have another copy of anything important and irreplaceable? Parity is not a substitute for backups. Plenty of ways to lose data besides failed disks, including user error.

There's nothing terribly lost, mostly just time.  I don't store important personal data on this array for that reason. If it were to die, all I would of lost was time.  My goal is to save myself time if at all possible.  I built this server many years ago but when it comes to the details of how everything works, I will admit I am not the most knowledgeable (if that isn't already apparent).

 

7 minutes ago, trurl said:

Rebuild makes the physical disks have the exact same contents as the emulated disks. That is all it can do.

 

So having said that, it seems if i want to keep the data and the fixed drives, the best move is to reset the array configuration?

[trurl]

3 minutes ago, brambo23 said:

the drives were not mountable until I did a file system check.  It repaired the issue again then I was able the mount the drives again

You did this on the physical disks again? I ask because repairing the emulated disks is the usual method.

 

4 minutes ago, brambo23 said:

the best move is to reset the array configuration?

If the physical disks are mountable then yes. Do they have lost+found folders after this additional repair?

[brambo23]

1 minute ago, trurl said:

You did this on the physical disks again? I ask because repairing the emulated disks is the usual method.

On the physical disks yes, I did not do anything with the emulated disks (that I know of)

2 minutes ago, trurl said:

If the physical disks are mountable then yes. Do they have lost+found folders after this additional repair?

I repaired, mounted, and looked in the drive itself again, found no folder or entity titled "lost+found"

 

[trurl]

OK. Should be good to New Config and let it rebuild parity.

 

[trurl]

Understanding parity can help make some sense of this confusion. It isn't magic or even complicated.

 

Since I just posted about this on another thread, I link it here:

 

 

[brambo23]

Happy to report that the data is back and the parity is rebuilding with no issues.

 

Appreciate all the help!