Udma crc error count

[Kjetil]

Hello everyone

 

I had an error showing up, saying "umma cry error count". So I decided to take the disc showing this error out of the server, and format it.

Writing over it completely, once.

 

Disc is ok. So I want to add it to the unraid again, and rebuild it. When I add it and start the unraid, I get a message saying that I got 1 unmountable disc (in this case disc 22). I get the choice to format this disc. And a message saying "A format is NEVER part of a data recovery or disc rebuild process".

 

Have I done something stupid when I removed the disc and formatted it (using a Mac mini) ? 

What is the correct way to rebuild the unraid now ? Parity is valid.

 

Hoping someone who is deep into unraid can help me do this rebuild the correct way.

 

Kind regards, Kjetil

 

[trurl]

CRC errors are connection problems, not disk problems.

 

Pretty much everything you did was wrong, but maybe not fatal.

 

Stop the array, unassign the disk, start the array with the disk unassigned. That will disable the disk and hopefully the emulated filesystem will be mountable.

 

After that post a new screenshot and diagnostics.

[Kjetil]

Hello.

 

Thanks for the help.

 

I did not go thru the Format unmountable disks. 

 

So in my mind when I formatted the disk I thought it would be the same as exchanging it for a new disk.

 

Just to be sure I don't do any more mistakes, how do I correctly unassigned the disk ?

I have another slot available, should I move the disc to a new slot (if there is connection problems to it) ?

 

 

[Kjetil]

Erasing a disc hopefully is not fatal, as the parity is valid and the disc can rebuild ?

[Squid]

10 minutes ago, Kjetil said:

Erasing a disc hopefully is not fatal, as the parity is valid and the disc can rebuild ?

If you format the emulated drive, the rebuild will reflect a formatted drive.  IE: You will lose data.  Formatting is never part of any rebuild operation.

[Kjetil]

Don't understand. If the disc fail, I add a new disc and it rebuilds the unraid. What's different when removing a disc, formatting it and adding it again ? From adding a completely new drive ?

 

[JorgeB]

Formatting outside the array and then re-add to rebuild is not a problem, though in that case the format part is pointless, formatting in the array is where many users run into trouble, expecting to rebuild the disk form parity after formatting.

 

When there's an unmountable disk the first thing to do is to check filesystem.

[trurl]

The reason it is unmountable is because you formatted it outside the array. If you had formatted the disk in the array then parity would have been updated to agree the disk was formatted, and so only a formatted disk could be rebuilt. But since you didn't format it in the array, parity should be able to emulate the contents for rebuild.

 

4 hours ago, Kjetil said:

how do I correctly unassigned the disk

When you stop the array, you will be able to select no disk for that assignment.

 

17 hours ago, trurl said:

Stop the array, unassign the disk, start the array with the disk unassigned. That will disable the disk and hopefully the emulated filesystem will be mountable.

 

After that post a new screenshot and diagnostics.

[Kjetil]

But can I not format it again inside the array ? As a new disc ? Preclear or what its called ?

 

I am really not tech savvy, and would appreciate very much a step to step guide on what to do from now ☺️☺️

Or maybe team viewer or similar ?

[itimpi]

2 minutes ago, Kjetil said:

But can I not format it again inside the array ? As a new disc ? Preclear or what its called

Not much point as the rebuild process would overwrite every sector on the disk thus destroying the result of a format  or clear if done outside the array.  If done with the disk IN the array you would end up erasing all its contents with no way to recover the data.

 

Follow the advice from @trurl for the next steps to take.

[trurl]

Just now, Kjetil said:

But can I not format it again inside the array ? As a new disc ? Preclear or what its called ?

We have already explained that if you format the disk in the array the only thing you will be able to rebuild is a formatted disk. A formatted disk is empty.

 

You don't need a clear or formatted disk to rebuild to. Rebuild will completely overwrite every bit of the disk regardless of what is already on the disk.

 

18 hours ago, trurl said:

Stop the array, unassign the disk, start the array with the disk unassigned. That will disable the disk and hopefully the emulated filesystem will be mountable.

When you start the array with the disk unassigned, Unraid will emulate the disk from parity. The emulated contents are exactly what will be rebuilt. 

 

18 hours ago, trurl said:

After that post a new screenshot and diagnostics.

Then we can see if the emulated disk is mountable. If it is we can proceed with rebuild. If not, we can try to repair the emulated filesystem before rebuilding.

 

Either way, after that any disk you assign there will be considered "new" and when you start the array the rebuild will begin.

[Kjetil]

Thanks guys. But I am just lost here... The unraid is stopped. Shall I first choose disc 22 as the 10tb ? And then "Start" to bring the unraid array online ?

[Kjetil]

[JorgeB]

16 minutes ago, Kjetil said:

Shall I first choose disc 22 as the 10tb ?

No, you should do what trurl already told you 19H ago:

 

19 hours ago, trurl said:

Stop the array, unassign the disk, start the array with the disk unassigned. That will disable the disk and hopefully the emulated filesystem will be mountable.

 

After that post a new screenshot and diagnostics.

 

[Kjetil]

Ok, sorry guys for being technically a rookie on raids. But if I start the unraid without disc 22 (disc 22 unassigned) - will not parity delete the data that was on disc 22 ? 

[JorgeB]

1 minute ago, Kjetil said:

will not parity delete the data that was on disc 22 ? 

What would be the point of having parity them? Parity, if still valid, will emulate the missing disk.

[Kjetil]

Ok, I am sorry that I don't understand this topic well enough. Hence these questions. I will start the array now without disc 22.

[Kjetil]

Array started, no error messages so far. Here is a screenshot and diagnostics.

federalreserve-diagnostics-20211218-1609.zip

[JorgeB]

Emulated disk mounted which is good news, now you can rebuild using the old or a new disk, just stop the array, assign the disk you want to use and start the array to begin rebuilding.

[Kjetil]

Rebuild started. I guess this message is normal ?

[JorgeB]

19 hours ago, Kjetil said:

I guess this message is normal ?

Yes.

[Kjetil]

Rebuild is complete and successful. I have added a diagostics here.

Thanks for good help all you guys ! Much appreciated.federalreserve-diagnostics-20211220-0711.zip

[JorgeB]

Looks good.

[Kjetil]

Looks good my side too. Thanks everyone for helping 😀