Anybody who builds their own pod is welcome to use RAID or not, and which RAID you choose will affect your final numbers. At Backblaze, we configure it as RAID

Anybody who builds their own pod is welcome to use RAID or not, and which RAID you choose will affect your final numbers. At Backblaze, we configure it as RAID 6 groups, each group is 15 drives which includes 2 parity drives. So you are down to 13/15 = 86.67 percent of the raw unformatted space BEFORE the overhead of ext4 which adds a little tiny bit extra. So after formatting in our datacenter we are left with about 116 TBytes of storage space for customer files. On the other hand, we use lossless compression on the customer's files before transmitting to the pod, so it can sometimes appear like we are fitting more than 116 TBytes of customer data on a pod, if that makes sense.