Hi 

 

I've got a server with 4tb drives or smaller and having read errors on one of my data disks. 

 

would it be possible to replace the parity with a new 12tb drive, then once the parity has been rebuilt on the new drive,  replace the bad data drive with the old parity drive? 

 

Thanks in advance!

 

 

Edited March 17, 20251 yr by Mkultra

That would be a Bad Idea™️

 

Replace the failing drive first

ok, thought so. the idea of buying a new 4tb drive doesnt fill me with joy!

If you can get the data off of it, you can just new-config parity with the new 12tb parity drive - assuming you trust the rest of the drives

ok, thanks for the advice!going to try and make that happen. is unbalanced still a good option? 

 

i know i sound like an amateur, but is it safe the move the data from the disk without damaging the files with a rebuild etc? 

4 minutes ago, Mkultra said:

ok, thanks for the advice!going to try and make that happen. is unbalanced still a good option? 

 

 

Yep

 

2 minutes ago, Mkultra said:

i know i sound like an amateur, but is it safe the move the data from the disk without damaging the files with a rebuild etc? 

 

Not sure what you mean

 

On 3/17/2025 at 1:03 PM, Mkultra said:

would it be possible to replace the parity with a new 12tb drive, then once the parity has been rebuilt on the new drive,  replace the bad data drive with the old parity drive? 

The parity swap procedure is designed for this exact Use Case as long as you only have 1 parity drive.

 

if you have 2 parity drives it might be a little more complicated - and if so (or you have questions) post diagnostics so we can see your exact configuration. 

2 hours ago, itimpi said:

The parity swap procedure is designed for this exact Use Case as long as you only have 1 parity drive.

 

if you have 2 parity drives it might be a little more complicated - and if so (or you have questions) post diagnostics so we can see your exact configuration. 

Didn't realize that it could be done with an already redballed drive, good to know!

21 minutes ago, Michael_P said:

Didn't realize that it could be done with an already redballed drive, good to know!

That is normally the way you would do it. In fact, the only way you can get parity swap to work when no disk is already disabled is if you disable the disk first. From that link:

Quote

IMPORTANT!!! This procedure REQUIRES that the data drive being replaced MUST be disabled first. If the drive failed (has a red ball), then it is already 'disabled', but if the drive is OK but you want to replace it anyway, then you have to force it to be 'failed', by unassigning it and starting and stopping the array. Unraid only forgets a drive when the array is started without the drive, otherwise it still associates it with the slot (but 'Missing'). The array must be started once with the drive unassigned or disabled. Yes, it may seem odd, but is required before Unraid will recognize that you are trying to do a 'Parity Swap'. It needs to see a disabled data disk with forgotten ID, a new disk assigned to its slot that used to be the parity disk, and a new disk assigned to the parity slot.

 

On 3/17/2025 at 9:21 AM, Mkultra said:

is it safe the move the data from the disk without damaging the files with a rebuild

No point in moving the data from the disk, since they will be rebuilt.

 

If you are concerned that the disk has important and irreplaceable files that would be lost if something goes wrong, then the best thing to do would be to copy (not move) them somewhere off the array (not to other disks in the already degraded array).

 

You must always have another copy of anything important and irreplaceable. Parity is not a substitute for backup.

5 minutes ago, trurl said:

That is normally the way you would do it. In fact, the only way you can get parity swap to work when no disk is already disabled is if you disable the disk first. From that link:

 

 

Yeah, I get it now - it was this bit that my brain was rejecting

 

If the drive failed (has a red ball), then it is already 'disabled',