Messages in this thread | | | Date | Wed, 12 Jun 2002 10:13:53 +0200 | From | Kasper Dupont <> | Subject | Re: RAID-6 support in kernel? |
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Allan Sandfeld wrote: > > I just looked at it. It is possible allright and the diagram looks ok. > > If you have 3 disks A,B and C the parity is calculated by dividing the diskw > into typical lines, in this example I use 3 like they use on the diagram. We > then have a parity per line and one per disk. You can only regenerate one > block per parity, but since you have two full independ parities you can > replace any two. > > A1 B1 C1 P1 (P1 = A1^B1^C1) > A2 B2 C2 P2 > A3 B3 C3 P3 > PA PB PC > (PA=A1^A2^A3) > > As you can see if you wish to chech the parity for one read line(eg.A1-C1), > you can check directly against the horizontal parity P1. But if you wish to > check the horizontal parity you need to read the entire diskarray!
I don't think I got that one. How many disks would you use, and how would you distribute the above fields across the disks? If you put each column on a disk you can handle any two lost blocks, but not two lost disks. Or would you use a total of 15 disks? Or do you have some way of placing them on 5 disks with 3 blocks on each disk?
-- Kasper Dupont -- der bruger for meget tid på usenet. For sending spam use mailto:razor-report@daimi.au.dk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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