Replacing/upgrading one of two parity drives

[sonofdbn]

I run 6.3.5 with a dual parity setup and 6 data drives. The two parity drives are 4TB and 8TB (so naturally the largest data drive is 4TB), and I want to replace the 4TB parity drive with an 8TB one. Is there anything special I need to do? Here's what I plan to do:

 

1. Do parity check

2. Stress test new drive (and since this will be a parity drive, there's no need to preclear)

3. Stop array and power down

4. Replace the old (smaller) parity drive with the new larger one

5. Power up

6. Start the array -> rebuilding of new parity drive starts

 

Some questions:

a. Can the array be used while rebuilding parity? (By "used" I mean running VMs and dockers and general reading/writing.)

b. Is it necessary/recommended to do a parity check after the rebuilding?

c. I run the server off a UPS. What would happen if there is a power failure and the UPS triggers a shutdown during parity rebuilding?