Messages in this thread | | | Date | Mon, 3 Jun 2002 10:28:14 +0200 (CEST) | From | Roy Sigurd Karlsbakk <> | Subject | Re: RAID-6 support in kernel? |
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> > RAID-6 layout: http://www.acnc.com/04_01_06.html > > If it is supposed to survive two arbitrary disk failures something is > wrong with that figure. They store 12 logical sectors in 20 physical > sectors across 4 drives. With two lost disks there are 10 physical > sectors left from which we want to reconstruct 12 logical sectors. > That is impossible.
Might be the diagram is wrong. Ok. But I know people like Compaq are already doing RAID-6.
> OTOH it is possible to construct a system with optimal capacity and > ability to survive any chosen number of disk failures. This can be > done using either a Reed-Soloman code or Lagrange interpolation of > polynomials over a finite field. > > However I guess those techniques would be inefficient in software.
Yeah? That's what the hardware RAID vendors all say, and I yet haven't seen one single test where Linux Software RAID can't beat hardware RAID. That is also after some testing I did on a high-end intel server at Compaq's lab in Oslo. How can RAID-6 be so much different?
roy
-- Roy Sigurd Karlsbakk, Datavaktmester
Computers are like air conditioners. They stop working when you open Windows.
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