I'm building a new pool and trying to plan the configuration. My server has 24 bays and will be used for data archiving and home media streaming. I'm optimizing for capacity and redundancy, and I'm not very concerned about speed. I also expect to be doing a lot more reading from the pool than writing.
I am using 12TB HGST Ultrastar HUH721212ALE600 drives. I can use 3 RAID-Z2 vdevs of 8 drives each or 2 RAID-Z3 vdevs of 12 drives each. Both configurations obviously have the same number of parity drives. The first configuration can only lose a maximum of any 2 drives without data loss, but the second configuration can lose a maximum of any 3 drives without data loss. If a favorable set of drives fail, then either can lose up to 6 drives without data loss. I understand RAID-Z3 has a higher cost for parity calculation, but I would expect that to only matter when writing to the drive (which I expect to do relatively rarely and I don't really care much in this case) and when recovering data due to either partial or complete drive failure in which case I will replace the failing drive. Resilvers would slower as well.
I think for my particular use case the 2 RAID-Z3 vdevs of 12 drives each is the better option.
Does anyone see any flaws in my reasoning?
I am using 12TB HGST Ultrastar HUH721212ALE600 drives. I can use 3 RAID-Z2 vdevs of 8 drives each or 2 RAID-Z3 vdevs of 12 drives each. Both configurations obviously have the same number of parity drives. The first configuration can only lose a maximum of any 2 drives without data loss, but the second configuration can lose a maximum of any 3 drives without data loss. If a favorable set of drives fail, then either can lose up to 6 drives without data loss. I understand RAID-Z3 has a higher cost for parity calculation, but I would expect that to only matter when writing to the drive (which I expect to do relatively rarely and I don't really care much in this case) and when recovering data due to either partial or complete drive failure in which case I will replace the failing drive. Resilvers would slower as well.
I think for my particular use case the 2 RAID-Z3 vdevs of 12 drives each is the better option.
Does anyone see any flaws in my reasoning?