On Wed, 2004-07-14 at 10:47, Marlier, Ian wrote: > Hey all... > > I'm looking for some help figuring out how to shrink a RAID1 device > that's mounted as root on a Red Hat system. > > The device setup is this: > Raiddev /dev/md0 > Device /dev/hda1 > Raid-disk 0 > Device /dev/hdb1 > Raid-disk 1 > > Hda and hdb are both 36GB ATA hard drives, and each currently has a > partition of about 33GB formatted as Linux RAID autodetect. Each also > has a swap partition. > > What I'd like to do is shrink partition 1 on each disk to around 16GB, > and then create a second RAID1, /dev/md1, with a new partition /dev/hda3 > and /dev/hdb3 (leaving the swap device alone.) > > I booted off a rescue disk with mdadm, resize2fs, fdisk, etc, and I was > able to shrink /dev/md0 down to 16GB. > > I then tried to delete /dev/hda1 and /dev/hdb1 using fdisk, and create 2 > new equally-sized partitions in the free space created. (/dev/hda1, > /dev/hda3, /dev/hdb1, /dev/hdb3, all type Linux RAID Autodetect). > Because /dev/hd[ab]1 is larger than /dev/md0, and the starting block of > the partitions is the same, the filesystem should remain intact. > > However, upon rebooting, I ran into a problem. /dev/md0 cannot be > mounted because of a problem with the superblocks. > > I figure that something needs to be done with mdadm to get it to > recognize the "new" /dev/hda1 and /dev/hdb1 as /dev/md0 -- but I don't > want to do a mdadm --create because that will overwrite the filesystem > already on the disks (I think?). > > Is this something that mdadm --assemble can do? If so, what switches > need to be fed to the command? > > Other suggestions? > > If your newly created partitions are > 16GB as stated, you should be able to recreate raid1 md0 using mdadm via your rescue disk. After the re-sync completes, you can reboot the machine. Remember, raid1 is mirroring :) Regards, Mike T. - 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
