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From: Phil Turmel <philip@turmel.org>
To: Chris Murphy <lists@colorremedies.com>
Cc: Roman Mamedov <rm@romanrm.ru>,
	linux-raid mailing list <linux-raid@vger.kernel.org>
Subject: Re: Raid 5 to 6 migration
Date: Fri, 01 Feb 2013 17:04:29 -0500	[thread overview]
Message-ID: <510C3BED.2030408@turmel.org> (raw)
In-Reply-To: <065BDBBE-7DB8-40CC-B1BC-8DCEE327F7C4@colorremedies.com>

On 02/01/2013 01:49 PM, Chris Murphy wrote:
> 
> On Feb 1, 2013, at 11:19 AM, Phil Turmel <philip@turmel.org> wrote:
> 
>> On 02/01/2013 01:16 PM, Roman Mamedov wrote:
>>>
>>> --layout=preserve will make it an order of magnitude faster. Read "man mdadm"
>>> for more details. (And "man md" to learn about things in general.)
>>
>> But will leave the array "unbalanced"--the 7th drive will never be used
>> for reads in normal (non-degraded) operation--reducing read performance.
> 
> Does this option mean, in effect, the 7th disk is just a parity disk? So, sorta like a hybrid RAID 5/RAID4.

Yes, with just the Q left on the 7th disk.  The remainder of the array
is the normal raid5 stripe.  See the manpage for the layout
"left-symmetric-6".

Phil

  reply	other threads:[~2013-02-01 22:04 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-02-01 17:17 Raid 5 to 6 migration Dominique
2013-02-01 17:50 ` Phil Turmel
2013-02-01 18:16   ` Roman Mamedov
2013-02-01 18:19     ` Phil Turmel
2013-02-01 18:49       ` Chris Murphy
2013-02-01 22:04         ` Phil Turmel [this message]
2013-02-01 22:38           ` Chris Murphy
     [not found]   ` <COL114-W137DD8871889508BBF087BC91C0@phx.gbl>
2013-02-01 18:22     ` Phil Turmel
2013-02-03 10:00       ` Roy Sigurd Karlsbakk
2013-02-03 14:30         ` Phil Turmel
2013-02-03 22:01           ` Robin Hill
2013-02-04 12:51       ` Dominique
2013-02-04 18:39         ` Phil Turmel
2013-02-05  0:58           ` Brad Campbell
2013-02-05 10:36           ` Dominique
2013-02-05 13:04             ` Phil Turmel

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