From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lars =?UTF-8?B?VMOkdWJlcg==?= Subject: Re: Reopen: 16 HDDs too much for RAID6? Date: Fri, 28 Mar 2008 11:27:00 +0100 Message-ID: <20080328112700.5d5dd662.taeuber@bbaw.de> References: <20080306100128.8daad6bd.taeuber@bbaw.de> <20080307114555.6ce17158.taeuber@bbaw.de> <20080328102002.a8b836b6.taeuber@bbaw.de> <200803281114.41018.bs@q-leap.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <200803281114.41018.bs@q-leap.de> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Hallo Bernd, Bernd Schubert schrieb: > Hallo Lars, >=20 > On Friday 28 March 2008 10:20:02 Lars T=C3=A4uber wrote: > > Hallo! > > > > Lars T=C3=A4uber schrieb: > > > I zeroed out all physical devices completely: > > > # for DEV in /dev/sd[c-r]; do dd if=3D/dev/zero of=3D$DEV; done >=20 > why not simply "mdadm --zero-superblock $DEV"? I just wanted to make clear, that there couldn't be anything left anywh= ere on the disk. I already learned about this option of mdadm. =20 > > > > > > Now the problem is gone. I don't know what really caused the prob= lem. > > > Many thanks for your suggestions. > > > > The problem has occured again. > > I'm not sure what the cause was, but the duplicated superblock is t= here > > again. But the raid fell apart before. So I suspect this occurs onl= y after > > the array was degraded. The discs are not defective so I tried to > > reassemble the array with the original discs again: monosan:~ # mda= dm -A > > /dev/md4 > > mdadm: WARNING /dev/dm-9 and /dev/dm-8 appear to have very similar > > superblocks. If they are really different, please --zero the superb= lock on > > one If they are the same or overlap, please remove one from the > > DEVICE list in mdadm.conf. > > > > How can I extract the superblocks to check if they are really ident= ically? >=20 >=20 > mdadm --examine /dev/dm-9 > mdadm --examine /dev/dm-8 I just reassembled the array for another test. Next time I'll have a de= eper look with this. > Do you have some kind of multipathing, which really could cause a ide= ntical=20 > superblocks on dm-9 and dm-8? Did you specify dm-9 and dm-8 in you=20 > mdadm.conf / assemble script or the real human readable lvm / multipa= th=20 > names? Here the conf file: monosan:~ # cat /etc/mdadm.conf=20 DEVICE /dev/sd[ab][0-9] /dev/dm-* ARRAY /dev/md2 level=3Draid1 UUID=3Dd9d31de2:e6dbd3c3:37c7ea09:882a64e5 ARRAY /dev/md3 level=3Draid1 num-devices=3D2 UUID=3Da8687183:a79e514c:c= a492c4b:ffd4384f ARRAY /dev/md4 level=3Draid6 num-devices=3D15 spares=3D1 UUID=3Dcfcbe07= 1:f6766d8f:0f1ffefa:892d09c3 ARRAY /dev/md9 level=3Draid1 num-devices=3D2 name=3D9 UUID=3Ddb687150:6= 14e76fd:28feefc0:b1aae572 All dm-* devices are really distinctive. I could post the /etc/multipat= h.conf too if you want. Thanks Lars -- To unsubscribe from this list: send the line "unsubscribe linux-raid" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html