From: Jon Nelson <jnelson-linux-raid@jamponi.net>
Cc: LinuxRaid <linux-raid@vger.kernel.org>
Subject: Re: unbelievably bad performance: 2.6.27.37 and raid6
Date: Mon, 2 Nov 2009 13:39:35 -0600 [thread overview]
Message-ID: <cccedfc60911021139o7cac1ad2rb70333d5fc8026e6@mail.gmail.com> (raw)
In-Reply-To: <bb145bd20910311259j7b2506c8v4e8907eb73598275@mail.gmail.com>
On Sat, Oct 31, 2009 at 1:59 PM, Christian Pernegger
<pernegger@gmail.com> wrote:
>> md0 : active raid6 sda4[0] sdc4[5] sdd4[4] sdb4[6]
>> 613409536 blocks super 1.1 level 6, 64k chunk, algorithm 2 [4/4] [UUUU]
>
> Why would you use a 4 disk raid6? If 50% of raw capacity is enough
> just go with raid10
With 4 disks, the ability to sustain *any two* devices going bad is a big bonus.
Using raid10 with two copies (1 original, 1 duplicate) on 4 disks
gives me 50% space but I can only sustain *1* failed device. I'm
guessing I'd have to go with raid10 with three copies (1 original, 2
duplicate) which is even worse (2/3 space lost). Did I just calculate
that all wrong?
--
Jon
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next prev parent reply other threads:[~2009-11-02 19:39 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-31 15:55 unbelievably bad performance: 2.6.27.37 and raid6 Jon Nelson
2009-10-31 18:43 ` Thomas Fjellstrom
2009-11-01 19:37 ` Andrew Dunn
2009-11-01 19:41 ` Thomas Fjellstrom
2009-11-01 23:43 ` NeilBrown
2009-11-01 23:47 ` Thomas Fjellstrom
2009-11-01 23:53 ` Jon Nelson
2009-11-02 2:28 ` Neil Brown
2009-11-01 23:55 ` Andrew Dunn
2009-11-04 14:43 ` CoolCold
2009-10-31 19:59 ` Christian Pernegger
2009-11-02 19:39 ` Jon Nelson [this message]
2009-11-02 20:01 ` Christian Pernegger
2009-11-01 7:17 ` Kristleifur Daðason
2009-11-02 14:54 ` Bill Davidsen
2009-11-02 15:03 ` Jon Nelson
2009-11-03 5:36 ` NeilBrown
2009-11-03 6:09 ` Michael Evans
2009-11-03 6:28 ` NeilBrown
2009-11-03 6:39 ` Michael Evans
2009-11-03 6:46 ` Michael Evans
2009-11-03 9:16 ` NeilBrown
2009-11-03 13:07 ` Goswin von Brederlow
2009-11-03 16:28 ` Michael Evans
2009-11-03 19:26 ` Goswin von Brederlow
2009-11-02 18:51 ` Christian Pernegger
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