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From: Andy Smith <andy@lug.org.uk>
To: linux-raid@vger.kernel.org
Subject: Re: 4 disks: RAID-6 or RAID-10 ..
Date: Fri, 17 Feb 2006 15:31:32 +0000	[thread overview]
Message-ID: <20060217153132.GA32687@strugglers.net> (raw)
In-Reply-To: <Pine.LNX.4.56.0602171445280.22063@lion.drogon.net>

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On Fri, Feb 17, 2006 at 03:14:37PM +0000, Gordon Henderson wrote:
> Still scratching my head, trying to work out if raid-10 can withstand
> (any) 2 disks of failure though, although after reading md(4) a few times
> now, I'm begining to think it can't (unless you are lucky!) So maybe I'll
> just stick with Raid-6 as I know that!

RAID-10 cannot survive the failure of *any* two disks as if two
disks in one of the mirrors died then the whole mirror would be lost
which loses you a segment of the upper stripe.  *If* a second disk
dies, then with 4 didks total you have 50% chance of it being the
one you're relying on.

If you require to withstand the loss of *any* two disks then you
need RAID-6.

-- 
http://strugglers.net/wiki/Xen_hosting -- A Xen VPS hosting hobby
Encrypted mail welcome - keyid 0x604DE5DB

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  reply	other threads:[~2006-02-17 15:31 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-17 11:10 4 disks: RAID-6 or RAID-10 Gordon Henderson
2006-02-17 11:44 ` berk walker
2006-02-17 11:54   ` Gordon Henderson
2006-02-17 12:07     ` Francois Barre
2006-02-17 15:14       ` Gordon Henderson
2006-02-17 15:31         ` Andy Smith [this message]
2006-02-17 15:56           ` Gordon Henderson
2006-03-05 18:23         ` Bill Davidsen
2006-03-05 20:59           ` Gordon Henderson
     [not found]             ` <440B5ABF.6000702@tmr.com>
2006-03-06 12:14               ` Gordon Henderson

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