Hi Unraid team, 

 

I had a disk die (disk4 in my array) in my unraids, when I was in the process of replacement of the one dead disk (disk 4 data disk), a second (disk 1 data disk) decided to also give up. 

I pulled both out of the unraid and connected to USB to SATA device to check how dead they were with some tools. One is completely dead and will not even detect, however the 2nd (the more recent) failure was actually readable via Paragon through windows. (She isn't healthy tho) 

 

My question is, is there a way to force unraid to believe (data disk 1) is okay, so I can use parity to rebuilt data disk 4, then once that is rebuilt use parity to rebuild on a new disk data disk 1?

 

data disk 4 simply wont detect - so no smart reports

data disk 1 fails smart test at either 10% or 90%

 

I run one parity disk and both drive failures are on data disks. Parity drive is good.

Edited July 28, 20232 yr by bennymundz

8 hours ago, bennymundz said:

My question is, is there a way to force unraid to believe (data disk 1) is okay, so I can use parity to rebuilt data disk 4, then once that is rebuilt use parity to rebuild on a new disk data disk 1?

Sort of, but it sounds like you are thinking the parity disk is more important than it actually is. Rebuilding a disk requires all the other drives to be healthy, so if disk 1 isn't healthy, the rebuild of both disks will have corrupt areas where disk 1 was unable to be read correctly. This very likely will result in unmountable file systems on both disks, which may or may not be recoverable depending on where the corruption is.

 

Unraid will fail the rebuild of disk4 as soon as it encounters an unreadable sector on disk1. So, the only way forward with any chance of success that I can think of is to use ddrescue to clone disk1 to a healthy drive of the same exact size. This will allow Unraid to read all the sectors, even if the data there isn't accurate, so at least the rebuild of disk4 can complete, albeit with data corruption in the areas that failed the read during the clone process.

 

It would be much better to simply recover the data from your backups.