From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nikolay Kichukov Subject: Re: add another disk to existing raid 0, ie grow raid 0 possible? Date: Tue, 14 Feb 2012 11:43:30 +0200 Message-ID: <4F3A2CC2.4090101@oldum.net> References: <4F212A59.1070008@oldum.net> <20120126215713.0c24db62@notabene.brown> <4F21396D.7030308@oldum.net> <20120209145054.4443a48b@notabene.brown> <4F352541.2050207@oldum.net> <20120213090727.1d06291f@notabene.brown> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120213090727.1d06291f@notabene.brown> Sender: linux-raid-owner@vger.kernel.org To: NeilBrown Cc: =?UTF-8?B?TWF0aGlhcyBCdXLDqW4=?= , linux-raid List-Id: linux-raid.ids -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hello Neil, Here is the result, I think I managed to reproduce it as it has converted the raid0 to raid4. so commands in sequence: mdadm --verbose --create /dev/md/mdtest --level=0 --raid-devices=2 --metadata=1.2 /dev/loop0 /dev/loop1 mdadm: chunk size defaults to 512K mdadm: array /dev/md/mdtest started. strace -o /tmp/foo -f mdadm --grow /dev/md/mdtest --raid-devices=3 --add /dev/loop2 mdadm: level of /dev/md/mdtest changed to raid4 mdadm: /dev/loop2 not large enough to join array mdadm: Need to backup 3072K of critical section.. mdadm: /dev/md/mdtest: Cannot grow - need a spare or backup-file to backup critical section mdadm: aborting level change The 3 devices are equal sizes, all 200MB in size: - -rw-r--r-- 1 root root 209715200 Feb 14 11:28 raid_device1.loopback - -rw-r--r-- 1 root root 209715200 Feb 14 11:28 raid_device2.loopback - -rw-r--r-- 1 root root 209715200 Feb 14 11:17 raid_device3.loopback Output of mdadm -E : http://pastebin.com/WBhgP4L5 Contents of /tmp/foo: http://pastebin.com/jcietEaa Let me know if you need any more information to debug this. Thanks, - -Nik On 02/13/2012 12:07 AM, NeilBrown wrote: > On Fri, 10 Feb 2012 16:10:09 +0200 Nikolay Kichukov > wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- >> Hash: SHA1 > >> Hi Neil, >> Do you think it will make sense to try to replicate using loop devices? > > It certainly won't hurt. It might not achieve anything though. > Give it a try ... it you manage to reproduce, let me know. > > Thanks, > NeilBrown -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJPOizCAAoJEDFLYVOGGjgXylEIAK0JwigUO+E+L0GqdlYoU/N8 5zdEBZ+0yu0VjsyKPAhOTz5g9348lNRPFyuQkOlGoDm3T06WxAbgo/Hh1kS2Q4IT sWjw2w9NQI6qE0sRJPZS7Xie57M/dLVvNGUcLGvYCYTqXZQlAZbMf0tr8BCg8A6F ddkvagi+QPyQg9NQultRhHwt10Ed6D2J1NFbnpoytoJy+27lwGfom1hmGKdtLVZG 2ZRoGtzk2yhomF8qgY4xujClZSaF7HaZc1eJ0FDDoUvQfEHEtjImSd/BbwAiUpsH zv8aNn2Gik5v1RAHq8eOCg148J/XY/4RVD05zKj7fQqnphiwZGdirSKWv9YQCN0= =VwH2 -----END PGP SIGNATURE-----