Hallo Bernd, Bernd Schubert <bs@xxxxxxxxx> schrieb: > Hallo Lars, > > On Friday 28 March 2008 10:20:02 Lars Täuber wrote: > > Hallo! > > > > Lars Täuber <taeuber@xxxxxxx> schrieb: > > > I zeroed out all physical devices completely: > > > # for DEV in /dev/sd[c-r]; do dd if=/dev/zero of=$DEV; done > > why not simply "mdadm --zero-superblock $DEV"? I just wanted to make clear, that there couldn't be anything left anywhere on the disk. I already learned about this option of mdadm. > > > > > > Now the problem is gone. I don't know what really caused the problem. > > > Many thanks for your suggestions. > > > > The problem has occured again. > > I'm not sure what the cause was, but the duplicated superblock is there > > again. But the raid fell apart before. So I suspect this occurs only after > > the array was degraded. The discs are not defective so I tried to > > reassemble the array with the original discs again: monosan:~ # mdadm -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 superblock 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 identically? > > > mdadm --examine /dev/dm-9 > mdadm --examine /dev/dm-8 I just reassembled the array for another test. Next time I'll have a deeper look with this. > Do you have some kind of multipathing, which really could cause a identical > superblocks on dm-9 and dm-8? Did you specify dm-9 and dm-8 in you > mdadm.conf / assemble script or the real human readable lvm / multipath > names? Here the conf file: monosan:~ # cat /etc/mdadm.conf DEVICE /dev/sd[ab][0-9] /dev/dm-* ARRAY /dev/md2 level=raid1 UUID=d9d31de2:e6dbd3c3:37c7ea09:882a64e5 ARRAY /dev/md3 level=raid1 num-devices=2 UUID=a8687183:a79e514c:ca492c4b:ffd4384f ARRAY /dev/md4 level=raid6 num-devices=15 spares=1 UUID=cfcbe071:f6766d8f:0f1ffefa:892d09c3 ARRAY /dev/md9 level=raid1 num-devices=2 name=9 UUID=db687150:614e76fd:28feefc0:b1aae572 All dm-* devices are really distinctive. I could post the /etc/multipath.conf too if you want. Thanks Lars -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
