From mboxrd@z Thu Jan  1 00:00:00 1970
From: NeilBrown <neilb@suse.de>
Subject: Re: Reshape RAID10 -> RAID1
Date: Wed, 26 Feb 2014 18:03:17 +1100
Message-ID: <20140226180317.10790f0e@notabene.brown>
References: <20140226060532.GA18630@kevin.peecee3.com>
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To: Charles Polisher <cpolish@surewest.net>
Cc: linux-raid@vger.kernel.org
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On Tue, 25 Feb 2014 22:05:32 -0800 Charles Polisher <cpolish@surewest.net>
wrote:

> Hi all,
>=20
> I hope to reshape a RAID10 (near,2) with 2 failed and physically
> removed members [_U_U] into a RAID1 hopefully [UU], for the
> benefit of seeing a healthy status.
>=20
> Is following proposed invocation correct?
>=20
>    mdadm --grow /dev/md2 --level=3D1

I think so.  If not, mdadm will complain.

It is quite easy to experiment: create some largish file, use losetup to tu=
rn
them into block device.  Then experiment with /dev/loop*

NeilBrown


>=20
> Details:
>=20
> root@mencius $ mdadm --query --verbose --detail /dev/md2
> /dev/md2:
>         Version : 1.1
>   Creation Time : Fri Jul 15 22:56:53 2011
>      Raid Level : raid10
>      Array Size : 1944916992 (1854.82 GiB 1991.59 GB)
>   Used Dev Size : 972458496 (927.41 GiB 995.80 GB)
>    Raid Devices : 4
>   Total Devices : 2
>     Persistence : Superblock is persistent
>=20
>   Intent Bitmap : Internal
>=20
>     Update Time : Tue Feb 25 22:00:46 2014
>           State : active, degraded=20
>  Active Devices : 2
> Working Devices : 2
>  Failed Devices : 0
>   Spare Devices : 0
>=20
>          Layout : near=3D2
>      Chunk Size : 512K
>=20
>            Name : localhost.localdomain:2
>            UUID : 971ee8b2:8d980355:0e5dfae9:c8bccd89
>          Events : 5326341
>=20
>     Number   Major   Minor   RaidDevice State
>        0       0        0        0      removed
>        1       8       19        1      active sync   /dev/sdb3
>        2       0        0        2      removed
>        3       8        3        3      active sync   /dev/sda3
> root@mencius $ uname -a
> Linux mencius 2.6.32-358.18.1.el6.centos.plus.x86_64 #1 SMP Wed Aug 28 16=
:14:04 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
> root@mencius $ mdadm --version
> mdadm - v3.2.6 - 25th October 2012
>=20
>=20
> Thanks,


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