changing MD device
I have a system up and running, the root directory is mounted on device /dev/md0 which is a raid1 of 2 IDE drives. My question is, how can I change it so that the my raid device is /dev/md1 not /dev/md0 and not loose the data. Originally I was thinking of booting with a rescue disk, breaking the raid1, and rebooting. Once rebooted create the raid device again as /dev/md1. Is there a simpler way to do this?
Why do I want to do this? I have several external FC arrays with software raid, and XFS file systems using an external log dev that is /dev/md0 which is defined as a raid1 on the same array. I want to be able to recover the external arrays - therefore my /dev/md0 on the backup machine needs to change to /dev/md1.
TIA
cluge
Quoted 1 line · Aaron Gee
I have a system up and running, the root directory is mounted on device
/dev/md0which is a raid1 of 2 IDE drives. My question is, how can I change it so that the my raid device is/dev/md1not/dev/md0and not loose the data. Originally I was thinking of booting with a rescue disk, breaking the raid1, and rebooting. Once rebooted create the raid device again as/dev/md1. Is there a simpler way to do this?
if your rescue disk contains mdadm you can use the
mdadm -A -U super-minor /dev/md1 /dev/hd?? once and the array will be started and the minor updated
L.
Signature · 6 lines
Luca Berra -- [email protected] Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \
Thanks for the advice, worked like a charm. I'm including the full procedure below for those that may need it in the future.
Quoted 4 lines
[email protected] wrote:
if your rescue disk contains mdadm you can use the mdadm -A -U super-minor/dev/md1/dev/hd?? once and the array will be started and the minor updated
How to change software raid minor number with RH installs.
1. On your running system get and install mdadm
2. mount a blank floppy, copy /sbin/mdadm to floppy
3. On your running system tar up /dev/md* (tar -cvf /mnt/floppy/dev.tar /dev/md*)
4. Boot from rescue disk - do NOT mount your linux install
5. At sh prompt, switch disks, mount the floppy that contains the tar file and mdadm
6. untar the devices (RH rescue disks only create /dev entries for arrays that it finds)
you should now have several /dev/md* entries. 7. Copy mdadm to /sbin annd run it using the command line above
example: mdadm -A -U super-minor /dev/md[new number here] /dev/1stdev /dev/2nd /dev/etc
8. cat /proc/mdstat - is the array running and synched now? Should be.
9. Mount your system useing the new device number where appropriate and modify /etc/fstab, /etc/raidtab and /etc/grub.conf to match your new raid settings 10.unmount all your system partitions and reboot
cluge