On 29/01/18 21:50, NeilBrown wrote: > By doing declustered parity you can sanely do raid6 on 100 drives, using > a logical stripe size that is much smaller than 100. > When recovering a single drive, the 10-groups-of-10 would put heavy load > on 9 other drives, while the decluster approach puts light load on 99 > other drives. No matter how clever md is at throttling recovery, I > would still rather distribute the load so that md has an easier job.
Not offering to do it ... :-) But that sounds a bit like linux raid-10. Could a simple approach be to do something like "raid-6,11,100", ie raid-6 with 9 data chunks, two parity, striped across 100 drives? Okay, it's not as good as the decluster approach, but it would spread the stress of a rebuild across 20 drives, not 10. And probably be fairly easy to implement. Cheers, Wol
