Tried to do a bit of research, but couldn't find a solid answer to this question:
2x WD Red 4TB,
2x spare HDD 2TB.
I know that the parity disk should be the largest or equal largest disk in the array. However I'd prefer to keep the data on the new WD Reds I've just bought.
Can I use the WD Reds for data disks, but use both regular HDDs as parity disks? As the two combined (4TB) is equal to the largest data disk size.