My current setup has 4 WD 4 TB drives in it, and an older 2 TB Seagate drive. I'd like to get rid of the old 2 TB drive. If I replace it with say a 6 or 8 TB drive, will it shift parity over to the new one? Will I have to rebuild the array? I know that the largest drive has to be the parity drive.
Second question, will I gain 2 TB of usable storage if the new drive shifts to being the parity drive?