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From: Kasper Dupont <kasperd@daimi.au.dk>
To: Derek Vadala <derek@cynicism.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-raid@vger.kernel.org
Subject: Re: RAID-6 support in kernel?
Date: Thu, 06 Jun 2002 10:28:28 +0200	[thread overview]
Message-ID: <3CFF1D2C.5861132C@daimi.au.dk> (raw)
In-Reply-To: Pine.GSO.4.21.0206051716530.16571-100000@gecko.roadtoad.net

Derek Vadala wrote:
> 
>   RAID-1 --------> RAID-5 (D0,D1,D2,D3,P0)
>               |--> RAID-5 (D0,D1,D2,D3,P0)
>    (four disks used for data, only one from each RAID-5 can fail)

Wrong, any three disks can fail. If the one RAID has only
one faulty disk, the other RAID can have any number of
faulty disks without loosing data.

> 
> With RAID-10:
> 
>   RAID-0 --------> RAID-1 (D0,D0)
>               |--> RAID-1 (D1,D1)
>               |--> RAID-1 (D2,D2)
>               |--> RAID-1 (D3,D3)
>               |--> RAID-1 (D4,D4)
>    (five disks used for data, one from each mirror can fail)
> 
> With RAID-50:
> 
>   RAID-0 --------> RAID-5 (D0,D2,D4,D6,P0)
>               |--> RAID-5 (D1,D3,D5,D7,P0)
> 
>    (two disks wasted only one from each RAID-5 can fail)
> 
> I believe that I/O performance would be similar for each
> configuration. I'll try to run some tests in the next few days.

I'd guess that depends on the access patterns.

-- 
Kasper Dupont -- der bruger for meget tid på usenet.
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  reply	other threads:[~2002-06-06  8:28 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <Pine.LNX.3.96.1020604144204.5024D-100000@gatekeeper.tmr.com>
2002-06-06  1:19 ` RAID-6 support in kernel? Derek Vadala
2002-06-06  8:28   ` Kasper Dupont [this message]
2002-06-06 11:57     ` Helge Hafting
2002-06-02 23:01 Roy Sigurd Karlsbakk
2002-06-03  0:33 ` Derek Vadala
2002-06-03  8:24   ` Roy Sigurd Karlsbakk
2002-06-03  9:25     ` Derek Vadala
     [not found]     ` <Pine.GSO.4.21.0206030213510.23709-100000@gecko.roadtoad.net>
2002-06-03  9:31       ` Vojtech Pavlik
2002-06-03 14:52         ` Kasper Dupont
2002-06-03 14:55           ` Vojtech Pavlik
2002-06-04 12:49           ` Roy Sigurd Karlsbakk
2002-06-04 15:49         ` Pavel Machek
2002-06-04 15:49         ` Pavel Machek
     [not found]         ` <20020604154904.J36@toy.ucw.cz>
2002-06-04 22:27           ` Kasper Dupont
2002-06-05  9:28           ` Roy Sigurd Karlsbakk
     [not found]           ` <3CFD3EE5.DAE3E2C9@daimi.au.dk>
2002-06-05  9:36             ` Roy Sigurd Karlsbakk
2002-06-03 17:33       ` Gregory Leblanc
2002-06-03 19:53         ` Ross Vandegrift
2002-06-04 20:20         ` Jakob Østergaard
2002-06-05  7:57           ` Luca Berra
2002-06-05 10:53             ` Jakob Østergaard
2002-06-05 19:42               ` Luca Berra
2002-06-04 18:50   ` Bill Davidsen

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