I was planning to upgrade my unRAID setup with dual parity drives.  Currently, the largest drives in the array are 4TB, including the parity drive.  I was going to install a 2nd 4TB parity drive but I just spotted a deal on an 8TB HGST NAS drive on Newegg that was too good to pass up.  I'm always looking to plan ahead for future upgrades and increasing the size of the parity drive is the first step.  With my existing setup, a data rebuild or parity check takes approximately 23 hours.  If I install the 8TB drive as parity, can I expect that time to double or will it just stop checking parity or rebuilding data after it reaches the 4TB boundary?

21 minutes ago, captain_video said:

With my existing setup, a data rebuild or parity check takes approximately 23 hours

 

That's a lot for 4TB, but it will depend on the hardware used, disk speed, how many different sizes, etc, my 4TB server takes around 10H for a parity check.

 

22 minutes ago, captain_video said:

If I install the 8TB drive as parity, can I expect that time to double or will it just stop checking parity or rebuilding data after it reaches the 4TB boundary?

 

The full 8TB will be checked, but the last 4TB should be much faster than the 1st 4, since it will be only one disk, so no or less bottlenecks, but it can also depend on the hardware.