Thanks Bob, really can't thank you enough. Just to be clear about this, I'd do these commands from the rescue disk after I have assembled the arrays and gone to the bash shell?
Much appreciated, James On 2 July 2013 22:44, Bob Proulx <b...@proulx.com> wrote: > James Allsopp wrote: > > One other point sda isn't the boot hard drive, that's the partitions > /sdb1 > > and sdc1, but these should be the same (I thought I'd mirrored them to be > > honest). > > I don't see sda anywhere. It might be a dual booting Windows disk? > Or other. But the BIOS will boot the first disk from the BIOS boot > order. BIOS boot order may be different from OS disk order. It can > be confusing. I might assume that BIOS sata0 is the same as the OS > disk sda but actually it often is different. Let's ignore this for > now. > > You have sdb1 and sdc1 mirrored into md1. I can see that because the > UUID is identical. > > > /dev/md1: > > Version : 1.2 > > Creation Time : Thu Jan 31 22:43:49 2013 > > Raid Level : raid1 > > Array Size : 1953510841 (1863.01 GiB 2000.40 GB) > > Used Dev Size : 1953510841 (1863.01 GiB 2000.40 GB) > > > Raid Devices : 2 > > Total Devices : 1 > > Persistence : Superblock is persistent > > > > Update Time : Tue Jul 2 13:49:55 2013 > > State : clean, degraded > > Active Devices : 1 > > Working Devices : 1 > > Failed Devices : 0 > > Spare Devices : 0 > > > > Name : Hawaiian:1 (local to host Hawaiian) > > UUID : a544829f:33778728:79870439:241c5c51 > > Events : 112 > > > > > > Number Major Minor RaidDevice State > > 0 0 0 0 removed > > 1 8 65 1 active sync /dev/sde1 > > That info is the same as: > > > /dev/md127: > > Version : 1.2 > > Creation Time : Thu Jan 31 22:43:49 2013 > > Raid Level : raid1 > > Array Size : 1953510841 (1863.01 GiB 2000.40 GB) > > Used Dev Size : 1953510841 (1863.01 GiB 2000.40 GB) > > Raid Devices : 2 > > Total Devices : 1 > > Persistence : Superblock is persistent > > > > Update Time : Tue Jul 2 13:49:29 2013 > > State : clean, degraded > > Active Devices : 1 > > Working Devices : 1 > > Failed Devices : 0 > > Spare Devices : 0 > > > > Name : Hawaiian:1 (local to host Hawaiian) > > UUID : a544829f:33778728:79870439:241c5c51 > > Events : 106 > > > > > > Number Major Minor RaidDevice State > > 0 8 49 0 active sync /dev/sdd1 > > 1 0 0 1 removed > > The UUIDs are identical. Therefore those two disks are mirrors of > each other. And note: > > > /dev/md1: (/dev/sde1) > > Update Time : Tue Jul 2 13:49:55 2013 > > /dev/md127: (/dev/sdd1) > > Update Time : Tue Jul 2 13:49:29 2013 > > sde1 is newer than sdd1. This seems consistent with it being the best > copy to keep. If it were the other way around I would think about > using the other one. But selecting the right master is important > since it is a component of the lvm. > > > How should I proceed from here? > > I would proceed as previously suggested. I would do this: > > mdadm --stop /dev/md127 > mdadm --manage /dev/md1 --add /dev/sdd1 > watch cat /proc/mdstat > > That will discard the older stale copy of the mirror on sdd1. It will > use sdd1 as a mirror of sde1. After doing the add the mirror will > sync and you can watch the progress using 'watch cat /proc/mdstat'. > Use control-c to interrupt it when you want to stop it. > > > For ruther information: > > /dev/sdb3: > > Preferred Minor : 126 > > ... > > /dev/sdc3: > > Preferred Minor : 126 > > ... > > That further information looked _okay_ to me. But I would still > change the md126 back to md0. > > mdadm --stop /dev/md126 > mdadm --assemble /dev/md0 --update=super-minor /dev/sdb1 /dev/sdc1 > cat /proc/mdstat > > Since it is clean now it will be stopped cleanly and reassembled > cleanly and no sync will be needed. The --update=super-minor will > reset the superblock with the updated md0 minor device number. > > Then update /etc/mdadm/mdadm.conf and rebuild the initrd. > > Bob >
