On Tue, 2012-09-04 at 11:45 -0700, Ross Boylan wrote: > Summary: mdadm on squeeze rewrites the UUID I give it with the > localhost, even if I do not specify localhost. I am trying to repair a > RAID for use on lenny with an existing UUID. Is there a way to avoid > the rewrite? Other solutions? > > Details > > A lenny host has two virtual machines, VM1 (lenny) and VM2 (squeeze). > There are two virtual disks, VD0 and VD1, whose 3rd partition forms > RAID1 (md1), intended for VM1. That same partition was in a RAID > before, but I grew it and so there is no RAID superblock near the end > anymore. I need to recreate the superblock without zapping the good data > on the partition. > > >From VM2: > # mdadm --create /dev/md1 --uuid=6f05ff4e:b4d49c1f:7fa21d88:ad0c50a9 > --metadata=0.90 --level=mirror --raid-devices=2 /dev/sdb3 missing > mdadm: array /dev/md1 started. > # mdadm --examine /dev/sdb3 > /dev/sdb3: > Magic : a92b4efc > Version : 0.90.00 > UUID : 6f05ff4e:b4d49c1f:f1c4dd81:d9ca9b38 (local to host > squeeze00) > > The man appears to say the UUID specified on the command line should > govern(*), but it doesn't. > > Some possible fixes: [snip] > 4) Find an appropriate rescue system image for lenny, start it in a VM, > and run mdadm from there. I wonder if stopping VM1's startup while it's > still in the initrd would be enough. The last option worked, with some work. I booted into the lenny VM specifying break=mount. At the prompt I had to do "modprobe md" to get things to work; then mdadm --create wrote the new superblock. Because the underlying partitions were out of sync, I created raid1 with only 1 of the partitions, and then added in the other. After it synced I restarted the VM and the newly expanded md1 was there.
For the record, md1 was a physical volume for LVM. So the complete sequence was to then pvresize /dev/md1 # makes the PV fill the whole md1 lvextend -L+1G myvg/usr # grow an LV that needed more room resize2fs /dev/myvg/usr # online resize of filesystem Although mdadm has some commands for --grow'ing the size of the md, I did not need to use any of them. Possibly that's because I used RAID1. Ross -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/1346800462.11821.9.ca...@corn.betterworld.us
