I have an MSA 2050 with 14 x 15K 900GB HDDs. From the MSA Gen5 Virtual Storage Technical Reference Guide, I follow the power of 2 for number of drives in a RAID 5 / 6 VDG and create an 8+1 RAID 5 VDG for pool A and a 4+1 RAID 5 VDG for pool B. Alternatively, I can also create two 6+1 RAID 5 VDGs and assign one to pool A and the other to pool B to balance the load across the two controllers.
Since the drives are HDDs that do not come close to exercising the bandwidth limits of the controllers, I want to use the first option of two different power of 2 size VDGs for the two pools. What are considerations that might justify using the second option of two same but not power of 2 size VDGs for the two pools instead of the first option?