From: "Peter Kovari" <peter@kovari.priv.hu>
To: linux-raid@vger.kernel.org
Subject: RE: RAID5 -> RAID6 conversion, please help
Date: Wed, 11 May 2011 02:08:00 +0200 [thread overview]
Message-ID: <002e01cc0f6f$7da2ceb0$78e86c10$@priv.hu> (raw)
In-Reply-To: <20110511093155.5b1a203e@notabene.brown>
> -----Original Message-----
> From: linux-raid-owner@vger.kernel.org
[mailto:linux-raid-owner@vger.kernel.org] On Behalf Of NeilBrown
> Sent: Wednesday, May 11, 2011 1:32 AM
> To: Peter Kovari
> Cc: linux-raid@vger.kernel.org
> Subject: Re: RAID5 -> RAID6 conversion, please help
> You have a RAID6 array in a non-standard config where there Q block (the
> second parity block) is always on the last device rather than rotated
around
> the various devices.
> The array is simply recovering that 6th drive to the spare.
> When it finished you will have a perfectly functional RAID6 array with
full
> redundancy. It might perform slightly differently to a standard layout -
> I've never performed any measurements to see how differently.
> If you want to (after the recovery completes) you could convert to a
regular
> RAID6 with
> mdadm -G /dev/md0 --layout=normalise
--backup=/some/file/on/a/different/device
> but you probably don't have to.
Thank you Neil, this explains everything.
I suppose the layout difference mostly affects - if affects - write
performance. Since this is a media server, with mostly read operations, I
probably will leave it as it is.
> The old meta on sdd will not have been a problem.
> What version of mdadm did you use to try to start the reshape?
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 10.04.2 LTS
Release: 10.04
Codename: lucid
$ mdadm --version
mdadm - v3.1.4 - 31st August 2010
$ uname -a
Linux FileStation 2.6.34-020634-generic #020634 SMP Mon May 17 19:27:49 UTC
2010 x86_64 GNU/Linux
Cheers,
Peter
prev parent reply other threads:[~2011-05-11 0:08 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-10 23:15 RAID5 -> RAID6 conversion, please help Peter Kovari
2011-05-10 23:31 ` NeilBrown
2011-05-10 23:39 ` Steven Haigh
2011-05-11 0:21 ` NeilBrown
2011-05-11 0:38 ` Dylan Distasio
2011-05-11 0:47 ` NeilBrown
2011-05-11 1:04 ` Dylan Distasio
2011-05-11 3:29 ` NeilBrown
2011-05-11 0:08 ` Peter Kovari [this message]
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