As I say, I do not think (maybe that is just a hope) that the offset did shift. I believe that because * there are two complete vg descriptions in the same part at the beginning of the device, before and after my vgcreate action * the older vg description has been replaced by the newer, actual one after the vgcreate action I made absolutely sure that the failing device had been flagged as failed and removed via mdadm --remove. When I added the new drive, the raid10 only ran on three disks. What do you think I should do? restore the beginning of the device using the file md0.txt? Then recreate the physical volume again using the -uuid switch? But what then? On Mar 27, 2013, at 5:29 , Stuart D Gathman <stuart@bmsi.com> wrote: > On Mar 26, Stuart D Gathman transmitted in part: > >> Why has the offset shifted? Possibilities: >> >> 1) different md driver version on knoppix (although using an older >> version would move the md superblock from end of drive to beginning of >> drive - shifting the opposite way). Or different options. BUT mdadm >> seemed to recognize your RAID, so let's >> discount this theory. >> >> 2) alignment options to pvcreate - but it still should have been seen by >> lvs! >> >> 3) the offset hasn't shifted, but you've written over the first few >> sectors with the empty VG. Is the 2nd human readable part, by any >> chance, missing the first part? You could post both parts for us to >> look at. > > 4) the shape of the md array changed. Say, you somehow didn't actually remove the failed drive before adding the replacement. What > does md raid10 do if you add a 4th disk to a 3 drive array? Add > it as a spare? Reshape, shuffling all your data? > > > _______________________________________________ > linux-lvm mailing list > linux-lvm@redhat.com > https://www.redhat.com/mailman/listinfo/linux-lvm > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/ _______________________________________________ linux-lvm mailing list linux-lvm@redhat.com https://www.redhat.com/mailman/listinfo/linux-lvm read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
