From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: Help with corrupted MDADM Raid6 Date: Sat, 14 Jun 2014 20:31:46 +1000 Message-ID: <20140614203146.5e99a84f@notabene.brown> References: <20140613202541.584dc8f1@notabene.brown> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/Upcm7f_RYwqh0HoeuOZbNvT"; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: "ptschack ." Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids --Sig_/Upcm7f_RYwqh0HoeuOZbNvT Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sat, 14 Jun 2014 11:54:58 +0200 "ptschack ." wrote: > Hi Neil, >=20 > I ran mdadm --examine on the devices (as opposed to the partitions) > and was surprised: > Apparently the superblocks are present on some the devices, even if I > remember differently. > I attached the output of mdadm to this mail. >=20 > For the sake of clarity, this is how the raid looked like before it > all went wrong: >=20 > 11 Drives (/dev/sd[abcdefghijk]) alltogether as a RAID 6. > 2 of those are spares (/dev/sd[jk]). > 1 is either close to failing of has failed (/dev/sdg). >=20 > I tried >=20 > mdadm --assemble --run /dev/md0 -v /dev/sd[abcdefghi] >=20 > which gave me >=20 > mdadm: looking for devices for /dev/md0 > mdadm: no RAID superblock on /dev/sdg > mdadm: /dev/sdg has no superblock - assembly aborted >=20 > So it seems I somehow have to restore the superblocks on drives > /dev/sd[ghijk], or at least on /dev/sd[ghi]. > Is this possible? Any help would be greatly appreciated! >=20 > Regards, > -P. Well, you've definitely made progress. You've found 6 of the devices. They all look consistent and it appears the array was completely coherent a= t=20 Mon Jun 9 21:52:48 2014 You think that the 7th device is dead or dying, so you just need to find 2 more (1 would do). Presumably these are sdh and shi, but it is very strange that we cannot find the superblock on either of them. When was the last time the machine was rebooted prio to the date given -9th Jun? Do you have boot logs from that time? What lines contain 'md'?? Particularly "bind" lines will show you exactly which devices were included. Maybe also try od -x /dev/sdh | grep '4efc a92b' If the superblock is at some strange location, that might find it. NeilBrown --Sig_/Upcm7f_RYwqh0HoeuOZbNvT Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.22 (GNU/Linux) iQIVAwUBU5wkkjnsnt1WYoG5AQKzYw//RLMNeYVD1s+Cr5Kgb+BVO0K5EIKDAzXO GEbXGRVY/EVvOwYCrqbv7wO225ZeTUQLdwLwyEUxn+fenNcgRNIOj2PcWNgVLo/x 3EotEY8ZtkalNVg+07N7sN6mPlqptSaDUxkF1CXyGoSgm09mbGvp6gv9AUBaXIor NAMsOSasYxMuNVvjjFWML3sJb8PvQCFRzSwyU0uZUHLGzeuupUcrV8EtHMvppHCY o0C7/71SSmAQVzmFxYWyu+8yd6rI+yM8L9/UwKtDjLfKf6efmFdzu8E572NG8PQD AKCFgvmk9IZM6WT8Bl6yqdTQ4DHhV9aIikItkRMuGEnr5t91mQ07jZXOvYflWOOy Jo5c2uhK+p2fexCsgq0W3SOvfXBfqn6UdggwcPtHGgj/XaX4oYwB3avp/16/05GO ZncZ+iTI92VQKnOMcqWLYE+Ouhjf+x2o4499TUFthUZ1NRHFJ0fEkt4lE2edJKg/ SQ0mOlm4+t44VjH8mx9ZPvmmMlm3Vz6Rkjyzjrptw+/ge2JhO7DnjdkY6mkrdWgH GxyMvnXUjKH9IOmDSt6S92iPhqpbJv3HbdXweM21+gqbk5wntyM3EvOrR3vpMLAQ 4wTltLYCUSTLFfm3HymBFcLHvRYN1No+dSVu9UhLilZ+Kzj1PgyUcTkPNHJ7KDis 0PGPZqo/Vwc= =ed5l -----END PGP SIGNATURE----- --Sig_/Upcm7f_RYwqh0HoeuOZbNvT--