Lost 2 drives (only one had data) with a 2-parity setup - help explain the warnings/reports I'm seeing please.

[xinil]

Hello I'm running 6.11.5 (haven't bitten the bullet for 6.12.# yet, but SOON.

 

I have two 14tb parity drives. Last week one of my array 6tb drives with zero data (clicking on 'View icon' in 'Main' screen array devices area  shows zero files/folders) stopped showing as installed/available. I don't have any other 6tb drives on hand so I added a new 14tb drive to my array. Wouldn't you know it, as soon as I spin the server back up one of my other 14tb array drives starts making crazy squealing/clicking noises. So now two drives are dead, fml. I remove the faulty 14tb drive, reboot and reassign the new 14tb to the previous failed disk #. I now have a 'Data-rebuild in process' with about 2days needed to complete. This all makes sense to me.

 

What I don't understand is the warnings I see on my "Shares" screen saying "Some or all files unprotected." I've technically lost two drives, but only one had data (~11tb) and the other had none (6tb empty.) Why cannot my parity safely emulate the data without there being an unprotected phase while data rebuild is in progress?

 

Current array screen, Disk 6 is the faulty 6tb I haven't removed from the array yet. Disk 1 is the new 14tb rebuilding.

 

Edited January 4 by xinil

[trurl]

You have one rebuilding and one missing disk, which is all 2 parity can do, so nothing is protected if another disk fails.

 

Doesn't matter if a disk is empty or not, an empty disk is not a clear disk. It still contains the metadata for the empty filesystem on the disk.

 

Even if disk6 happened to be a clear disk, Unraid won't remember whether or not all of its bits are zero so considers it to have bits that are part of current parity.

 

So you currently have no redundancy in your array.

[xinil]

Thanks trurl, very enlightening! That answers my question perfectly.

Follow up question - is the only way to 'fix' the redundancy issue to replace the missing disk? Can I remove the disk someway to rebuild the metadata without it? Pros/cons, would take too long, not worth struggle (e.g. just get another disk?) Thanks!

[trurl]

Rebuilding disk6 would be simplest. The alternative is to New Config without disk6 and rebuild parity, but not until disk1 rebuild completes.

 

If current rebuild of disk1 isn't very far along, you could cancel it, replace disk6, then rebuild both at once.