From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [BUG?] Grow on raid0 causes a level change to raid4 on metadata v1.2 Date: Tue, 27 Nov 2012 11:38:32 +1100 Message-ID: <20121127113832.51544a66@notabene.brown> References: <8565BDA60DEA9E4C91B1047AD1958FBE1DEC60DA@IRSMSX104.ger.corp.intel.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/f=wUIIw0rmdBV4TUdNzOX1j"; protocol="application/pgp-signature" Return-path: In-Reply-To: <8565BDA60DEA9E4C91B1047AD1958FBE1DEC60DA@IRSMSX104.ger.corp.intel.com> Sender: linux-raid-owner@vger.kernel.org To: "Tomczak, Marcin" Cc: "linux-raid@vger.kernel.org" , "Dorau, Lukasz" List-Id: linux-raid.ids --Sig_/f=wUIIw0rmdBV4TUdNzOX1j Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Fri, 23 Nov 2012 14:06:09 +0000 "Tomczak, Marcin" wrote: > Hi. There is a problem when I try to resize raid0 by adding disk to raid= =20 > volume. I have checked the problem on mdadm v3.2.3 and on a code from=20 > neil_master branch. >=20 > OS: Red Hat 6.3 GA > reproduction: always > system disk: sda > other disks: sdb, sdc, sdd >=20 >=20 > I. mdadm version: v3.2.3 >=20 > # mdadm -CR /dev/md/vol metadata=3D1.2 -l 0 --size=3D4G -n 2 /dev/sdb /de= v/sdc > # mdadm -G /dev/md/vol -n 3 --add /dev/sdd > mdadm: /dev/md/vol: could not set level to raid4 >=20 >=20 > II. mdadm version: branch neil_master >=20 > SHA1 ID: 30d48159710996be7770bfbfbddc826317b561aa > Monitor: don't complain about non-monitorable arrays in mdadm.conf > Author: NeilBrown 2012-10-24 04:09:09 > Committer: NeilBrown 2012-10-24 04:09:09 >=20 > # mdadm -CR /dev/md127 --metadata=3D1.2 -l 0 --size=3D15G -n 2 /dev/sdb /= dev/sdc --size isn't honoured for RAID0 (or Linear). I should probably do something about that - generate a warning at least. > # mdadm -G /dev/md127 -n 3 --add /dev/sdd > mdadm: level of /dev/md127 changed to raid4 > mdadm: added /dev/sdd > mdadm: this change will reduce the size of the array. > use --grow --array-size first to truncate array. > e.g. mdadm --grow /dev/md127 --array-size 47185920 This happens because the metadata has a size recorded in it, but it is being ignored, which results in confusions. > # cat /proc/mdstat > Personalities : [raid0] [raid6] [raid5] [raid4] > md127 : active raid4 sdd[3] sdc[1] sdb[0] > 78107648 blocks super 1.2 level 4, 512k chunk, algorithm 5 [3/3] [U= UU] >=20 >=20 > What do you think about this mdadm behaviour? Not ideal, but not a big problem if you avoid trying to set --size for RAID= 0. NeilBrown --Sig_/f=wUIIw0rmdBV4TUdNzOX1j Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (GNU/Linux) iQIVAwUBULQLiDnsnt1WYoG5AQIwWg//blzJX9vBZSqNfsFMeSIQ1oe5tsSih/nB DxWlS0hNt/dnQfa+QyVxlHPKCFds/ICu1tAY6vqIaZgmBRTo4AsD99C4zKkERCyT iVlBRM6mqom0hxJs/YIE5CIFrqo8xpqZx4ePRPy2b+MGYjiHN+N6JICJSBKyE5YX gIvQr5d7xJtn5EJ5W3LVMkVkDLfausLWwV24HqiMSfmC5kDndISLRRbMTJVLexCw pOMeQ82n8J7S+zPsPueLElAvkncbU8FWfPj4eUcBRmWFD2JRcaGIv14sTHF9LE1J cJ6chcEMyR8RGkYDJUJPjMsmBS5axlUFCnOkzk/HPiydPvaLk17lzztQ3eG9aVQl Js2kXpx3a3xD3uMjcn+SeeevJpFzSbbMaOgYj9OFGr/a2+RS23aEEjWORPZNbd+r dKmV75lhRTnXZoqz5tLAyV9GU1pO8pj6wSX7k/TnmRvV1D1+qxJQCX9FOyIKlnfp 43kc6VfT80uo3Ssm5ZHcC452+4RWUkxrKkWxNORp8db2vYlypVs5vl2nyckVW51q tJ9GKUaautr8fJZhV71EicuyJmDsvZBDEbEy+cGcEj92dDQleEmYCowy9WWfRyaD 3m5RNZ48TCsFnMCfA4jy3c/AXg66Wc+4ArPL3AiGCL02hkyjdjPpmZFuqxqsOc/B Q1+NCzt97qI= =81yO -----END PGP SIGNATURE----- --Sig_/f=wUIIw0rmdBV4TUdNzOX1j--