I'm replacing my 2 parity drives with larger ones.  My question is when rebuilding parity if I replace the drives one at a time can/will they rebuild using the other parity drive, or will it read from all the disks?

If it reads from everywhere I'll just replace both at the same time, but if they rebuild from each other I'll go 1 at a time and save the array the IOPS.

 

Thanks

6 minutes ago, mdr6273 said:

read from all the disks

Parity2 isn't even the same as parity. If parity2 were the same as parity, then it could only serve as a backup to parity. Since it is an independent and different algorithm, together both parity allows you to rebuild 2 data disks at the same time.

 

So each parity disk has to be built by reading all the other disks.

So then replacing both at the same time would have the fewest iops, or does it matter?

 

Thanks for the quick reply...

Faster to do both at once but if you do them one at a time you still have the protection of the one that isn't being rebuilt.