> > > > > 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.
> Could be the case, so until I find another description I will
> still not know how RAID-6 works.
Below is a (patented?) version that works. This is from the linux-raid list
> A1 A2 (P1) (PA)
> (P2) (PB) B2 B1
> C4 C3 (PC) (P3)
> (PD) (P4) D3 D4
>
> Disclaimer: I took that from Patent 6,353,895. If you look it up you'll see
> a lot of different schemes and discussion of XOR-based RAID 6, in language
> disguised as English. You'll also see that I'm listed as the inventor.
> That's four companies back for me, but my current employer unknowingly
> has some rights to it, so I hope it will see the light of day sometime.
>
> Dale Stephenson
> [email protected]
--
Roy Sigurd Karlsbakk, Datavaktmester
Computers are like air conditioners.
They stop working when you open Windows.