Replacing parity drives with larger capacity.

[tjsyl]

Found and read a 2020 topic about this but my situation is a bit different so I figured I would start a new topic.  2- 4TB parity drives, 5- 4TB in the array, 2- 8TB in a Mirror for all my Media.  I have 4 "new" 8TB drives that I am preclearing on my test UR server at the moment.  I am physically moving the drives from a Z820 to an entirely different PC but plan on just moving my flash drive over. I want to replace the parity drives (2x4TB) with 2 8TB drives. After booting up on the new hardware do I need to do both parity drives at the same time or one at a time?  After the parity rebuild is done I will transfer the Media data off the Mirror array and rope those 2 8TB drives into the Unraid Array. I am going to add 2 of those 8TB drives to the "in case shit" box with the other spare 4TB spare drives I have. 
 

[JonathanM]

You can do the parity drives one at a time to maintain redundancy.

[tjsyl]

Ty, I guess I knew that.  I guess I just want to do both at once to cut down on the rebuild time.

[itimpi]

4 hours ago, tjsyl said:

I guess I just want to do both at once to cut down on the rebuild time.

You can do that if you do not mind your data drives being unprotected until the parity rebuilds complete.