Triple-Parity RAID and Beyond - ACM Queue: "A ClassificationI reject this RAID-7 terminology. Or, rather, I find this terminology not useful - not useful for thinking about, explaining, extrapolating. If Marketing needs to use RAID-7, fine, let them - I will translate to what
for Triple-parity RAID
None of the existing RAID classifications apply for triple-parity RAID. ... The next obvious choice is RAID-7, but rather than applying the designation merely to RAID with triple-parity protection, RAID-7 should be a catch-all for any RAID technique that can be extended to an arbitrary number of parity disks. Specific techniques or deployments that fix the number of parity disks at N should use the RAID-7.N nomenclature with RAID-7.3 referring to triple-parity RAID, and RAID-5 and RAID-6 effectively as the degenerate forms RAID-7.1 and RAID-7.2, respectively."
'via Blog this'
The original RAID terminology was never coherent, arbitrary numbers, mixing considerations like bit, byte, and block level, dedicated parity disk versus rotating the parity, etc.
More and more, I am starting to use meaningful notations like
- Rd+p = redundancy, with d data disks and p parity (or other) disks.
- e.g. assuming striping at fixed size block level, and that all rotate parity
- Rd+1 = classic RAID-4, with d data disks and 1 parity disk,
- R4+1 = 4 data disks + 1 parity disk
- R2+1 = 2 data disks + 1 parity disk
- R3+1 = three data disks + 1 parity disk
- R1+1 = ?? arguably, a mirror, see below
- Rd+2 = d data disks + 2 parity = classic RAID-6
- Rd+3 = RAID-7 as proposed above, with triple parity