Why No RAID-DP in the Wild
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This came up in a recent discussion and I have no answer for it. NetApp's proprietary RAID level known as RAID-DP is known to have some awesome performance characteristics around RAID 6-like reliability without the heavy performance issues of RAID 6. RAID-DP is the dual parity version of RAID 4 (just as RAID 6 is the dual parity child of RAID 5.) It could also be called RAID 4.2 using a different naming convention system.
The question is, why is no one making a generic RAID 4.2 implementation for normal systems? Obvious vendors that I would expect to see doing this would be Adaptec and LSI on the hardware side and Linux (MD RAID) and Oracle (ZFS RAID) on the software side. Yet no one seems to even be researching this topic. Any thoughts as to why?
