Messages in this thread | | | Date | Wed, 8 Feb 2006 21:58:03 +0000 | From | Pavel Machek <> | Subject | Re: FYI: RAID5 unusably unstable through 2.6.14 |
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Hi!
> >If 1 disk has a 1/1000 chance of failure, then > >2 disks have a (1/1000)^2 chance of double failure, and > >3 disks have a (1/1000)^2 * 3 chance of double failure > >4 disks have a (1/1000)^2 * 7 chance of double failure > > After the first drive fails you have no redundancy, the > chance of an additional failure is linear to the number > of remaining drives. > > Assume: > p - probability of a drive failing in unit time > n - number of drives > F - probability of double failure > > The chance of a single drive failure is n*p. After that
<pedantic> Actually it is not. Imagine 100 drives with 10% failure rate each. You can't have probability of 1000%... </>
Pavel -- Thanks, Sharp! - 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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