Date: Mon, 10 Jul 2006 02:45:15 -0700 (PDT) From: "R. B. Riddick" <arne_woerner@yahoo.com> To: Stanislav Sedov <stas@310.ru>, freebsd-geom@freebsd.org Subject: Re: new class / geom_raid5 Message-ID: <20060710094515.1539.qmail@web30310.mail.mud.yahoo.com> In-Reply-To: <20060710133121.1836230d@localhost>
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--- Stanislav Sedov <stas@310.ru> wrote: > На Thu, 6 Jul 2006 15:42:09 -0700 (PDT) > "R. B. Riddick" <arne_woerner@yahoo.com> записано: > > My proposal for > > geom_raid5 > > is ready so far... > > > > If somebody wants to test it, he or she can download it from > > http://home.tiscali.de./cmdr_faako/geom_raid5.tbz > > How do you handle data recovery in case of crash of one of providers? > Hmm... As far as I understood the RAID5 idea, it is the following "trick": A XOR B XOR C = P A = P XOR B XOR C B = P XOR A XOR C C = P XOR A XOR B > All raid5 implemetations use different ECC algorithms for this, > like Reed-Solomon codes etc. > Hmm... I dont know so much about coding theory... I know that ECC means "error correction code" and I think the above formula describes an ECC, that can correct a missing bit, if we already know which bit is missing... E. g.: If we have the valid codewords 10 and 01, then we cannot say what 11 means, unless somebody tells us the second bit is a really very bad bit. > I haven't looked deeply into the code, but it seems there is no > any such algrithms implemeted there. Do you just duplicate data > on all providers? > Hmm... "duplicate data on all providers"... That sounds like a RAID1 / MIRROR... I am sorry, that my code is so bad, that it looks like MIRROR code... Maybe you should have a look at my newest version (I changed some things, but it is still mostly untested)? I have heard, that code inspection and tests should be done by somebody, who did not write it... So I would be glad, if somebody helps me here (of course I will do some tests, too, although I am a little bit annoyed by the BIOS-beeps already)... Should I use more but shorter functions? -Arne __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com
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