From: Phil Turmel <philip@turmel.org>
To: John Drescher <drescherjm@gmail.com>
Cc: linux-raid@vger.kernel.org
Subject: Re: mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
Date: Fri, 26 Oct 2012 17:04:43 -0400 [thread overview]
Message-ID: <508AFAEB.2030000@turmel.org> (raw)
In-Reply-To: <CAEhu1-6MpArC4AehLdfUX-zabspB_Dn6j2R20CGUwv8NSHEPwQ@mail.gmail.com>
On 10/26/2012 04:31 PM, John Drescher wrote:
> I got the following message when trying to convert a 2 disk raid1 to a
> 6 disk raid 6 in a 3.3.8 kernel:
>
> fileserver1 btrfs-root # mdadm --grow /dev/md3 --level=6 --raid-devices=6
> mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first.
>
> Fileserver1 btrfs-root # uname -a
> Linux fileserver1 3.3.8-gentoo-fileserver1-raid1 #3 SMP Thu Jul 12
> 20:06:18 EDT 2012 x86_64 Intel(R) Xeon(R) CPU E31230 @ 3.20GHz
> GenuineIntel GNU/Linux
>
> fileserver1 btrfs-root # mdadm --version
> mdadm - v3.2.6 - 25th October 2012
>
> fileserver1 btrfs-root # mdadm -D /dev/md3
> /dev/md3:
> Version : 1.2
> Creation Time : Wed Sep 28 16:03:56 2011
> Raid Level : raid1
> Array Size : 1874607039 (1787.76 GiB 1919.60 GB)
> Used Dev Size : 1874607039 (1787.76 GiB 1919.60 GB)
> Raid Devices : 2
> Total Devices : 6
> Persistence : Superblock is persistent
>
> Update Time : Fri Oct 26 16:24:22 2012
> State : clean
> Active Devices : 2
> Working Devices : 6
> Failed Devices : 0
> Spare Devices : 4
>
> Name : fileserver1:3 (local to host fileserver1)
> UUID : df2200d4:3ba5d29c:524dc437:35d663ea
> Events : 785
>
> Number Major Minor RaidDevice State
> 0 8 116 0 active sync /dev/sdh4
> 1 8 4 1 active sync /dev/sda4
>
> 2 8 244 - spare /dev/sdp4
> 3 8 196 - spare /dev/sdm4
> 4 8 212 - spare /dev/sdn4
> 5 8 228 - spare /dev/sdo4
The "Used Dev Size" must be a multiple of the target chunk size, and the
smallest allowed chunk size is 4K.
> Would upgrading the kernel avoid needing to reduce the size of the
> array? If not I assume I have to reduce the size of the btrfs
> filesystem then resize the array to 1874604032. Is that correct?
Upgrading the kernel won't help. For a 4K chunk size, 1874607032
sectors is correct. For other chunk sizes, you'll have to shrink a bit
more (1874607039 == 0x6FBC3BBF).
HTH,
Phil
next prev parent reply other threads:[~2012-10-26 21:04 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-26 20:31 mdadm: Cannot convert RAID1 of this size - reduce size to multiple of 4K first John Drescher
2012-10-26 21:04 ` Phil Turmel [this message]
2012-10-26 22:36 ` John Drescher
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