From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: mdadm raid6 recovery status Date: Fri, 30 Mar 2012 06:41:45 +1100 Message-ID: <20120330064145.6747fff0@notabene.brown> References: <20120328151148.035bd737@notabene.brown> <20120329102704.14b08f2a@notabene.brown> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/8vYwYjtdvJgy6J4pp5hR=IE"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: "Paramasivam, Meenakshisundaram" Cc: "linux-raid@vger.kernel.org" List-Id: linux-raid.ids --Sig_/8vYwYjtdvJgy6J4pp5hR=IE Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Thu, 29 Mar 2012 18:47:14 +0000 "Paramasivam, Meenakshisundaram" wrote: >=20 > Clarification: > >>should I do new array creation=20 > I meant running newfs on assembled 12 TB array, and restore data from bac= kup, to resolve "df" reporting problem. I would suggest asking on=20 linux-ext4@vger.kernel.org be sure to give lots of details - kernel version etc. It would be worth running=20 fsck -n /dev/md2 first and see if it reports anything strange. Maybe just a fsck will fix it. NeilBrown >=20 > ________________________________________ > From: Paramasivam, Meenakshisundaram > Sent: Thursday, March 29, 2012 1:33 PM > To: NeilBrown > Cc: linux-raid@vger.kernel.org > Subject: RE: mdadm raid6 recovery status >=20 > Good news: Got ALL of our data back. [Actually it was 4.96TB not 7TB]. > mdadm is a good one. >=20 > Bad news: "df" is reporting wrong, while "du" is showing full size. > # df -kl /myarray > Filesystem 1K-blocks Used Available Use% Mounted on > /dev/md2 11537161976 162432 10950945196 1% /myarray > # du -sk /myarray > 5326133556 /myarray > # >=20 > I never looked into du or looked in depth of the files & folders and simp= ly got mislead by reported "df" usage; data was there all along. We definit= ely want "df" for the array's filesystem (ext3) to report right. >=20 > Now that we are backing up all of the data (at 400 Mbps) over network, I = want to know if "df" reporting can be fixed easily or should I do new array= creation and restore data from backup. >=20 > We are ordering a new RAID card, just to be on safer side. >=20 > Sundar >=20 > ________________________________________ > From: NeilBrown [neilb@suse.de] > Sent: Wednesday, March 28, 2012 7:27 PM > To: Paramasivam, Meenakshisundaram > Cc: linux-raid@vger.kernel.org > Subject: Re: mdadm raid6 recovery status >=20 > On Wed, 28 Mar 2012 12:49:18 +0000 "Paramasivam, Meenakshisundaram" > wrote: >=20 > > [root@in-rady-neuro9 ~]# df -kl /myarray > > Filesystem 1K-blocks Used Available Use% Mounted on > > /dev/md2 11537161976 162432 10950945196 1% /myarray > > Should be 7TB of used space. >=20 > This is bad. Something has happened to your filesystem. > It is almost as though someone ran "mkfs" on the array. > I don't know much about recovery after such an action, but I doubt you > will get much back. >=20 > > > > [root@in-rady-neuro9 ~]# cat /proc/partitions > > major minor #blocks name > > > > 8 0 438960128 sda > > 8 1 512000 sda1 > > 8 2 51200000 sda2 > > 8 3 387247104 sda3 > > 8 16 1953514584 sdb > > 8 32 1953514584 sdc > > 8 48 1953514584 sdd > > 8 64 1953514584 sde > > 8 80 1953514584 sdf > > 8 96 1953514584 sdg > > 8 112 1953514584 sdh > > 8 128 1953514584 sdi > > 253 0 346226688 dm-0 > > 253 1 40992768 dm-1 >=20 > No md2 ??? >=20 > > > > sd[b-i] are raid devices > > > > [root@in-rady-neuro9 ~]# mdadm --detail /dev/md2 > > /dev/md2: > > Version : 0.90 > > Creation Time : Fri Dec 16 17:56:14 2011 > > Raid Level : raid6 > > Array Size : 11721086976 (11178.10 GiB 12002.39 GB) > > Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB) <<<=3D=3D=3D=3D= =3D=3D Wrong! Should be 7TB of used array space. >=20 > "Used Dev Size" isn't "how much of the array is used by the filesystem" - > mdadm doesn't know anything about filesystems. > It is "How much of each individual device is used by the array", which is > usually a little less than the size of the smallest device. > So 2TB is correct here. >=20 >=20 > NeilBrown >=20 >=20 --Sig_/8vYwYjtdvJgy6J4pp5hR=IE Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iQIVAwUBT3S6+Tnsnt1WYoG5AQIk4w//YRgDYjivDWIdem/7XIWrOCxrQhPMAjoL JU80sPK2GaYFdVjRuqgKMa4PU5p+8x7dr7hQBTBvOuJImPwPFGWaLtVbaKmlIuAE M/SGf8ugCvs2oRBEIZr4cnRPlOw0HPMedLZmalu22pLdRYO4gBbj3d/gL4UXiC4l iDijJFpEoN1OQIuQUv6wcQzmhZrUgN9cERJj20zh1MdlywdJ0G/3g3vFz0NZffu7 g9kXPBA+3zuSmFrZhbkDWRxUK3snGVCZoNMmipemVFfSgRJeLet/VU8De9EiZfXR Vacgh0Cbw6Fq2cA2nFJTm6haiL+TJcoqu8y5J3saQuSWqCZQ9DkErz9vUzF8quak YHfZ1yf7Mdj0w5hK/FbJsIx58fj69t9QtFNUp1jxFbwlEEgdSwCOEpE2Ng4jgg+i Dm9CbOvbehSF2lN7bkH6V3eCthufoXmNz6f22Mw5ZN4Fl/4IaKagMCuBiTEESUlf IcwaOCMqaMr0ABd0b9+SBoANmQRbKfB/3Zwqvf0wqm/tBV5z7boa/ICL9z8ReV72 OlOwXgdgLmXIEGbm4vm1bNomX2IrM6XmQaB9f/3YFxd3yDERp2rA5F/E/0qgHSpZ 81/Abp2bqAzhO1HPJd8XnnhiVBbpV1sZzsXgiMCufLTLNGqIGTkf69z9AZp9RdAx cyizOUPgh1A= =Z6jw -----END PGP SIGNATURE----- --Sig_/8vYwYjtdvJgy6J4pp5hR=IE--