On Fri, Nov 11, 2022 at 09:03:45AM +0100, hw wrote:
On Thu, 2022-11-10 at 23:12 -0500, Michael Stone wrote:The advantage to RAID 6 is that it can tolerate a double disk failure. With RAID 1 you need 3x your effective capacity to achieve that and even though storage has gotten cheaper, it hasn't gotten that cheap. (e.g., an 8 disk RAID 6 has the same fault tolerance as an 18 disk RAID 1 of equivalent capacity, ignoring pointless quibbling over probabilities.)so with RAID6, 3x8 is 18 instead of 24
you have 6 disks of useable capacity with the 8 disk raid 6, two disks worth of parity. 6 disks of useable capacity on a triple redundant mirror is 6*3 = 18.