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There is obviously more than one way to clone a linux install, but here’s the way I used most recently, when upgrading a 500G RAID1 volume on a 3ware HBA to 2T.

Fortunately, we had two free slots available, so we just inserted the new 2T drives into the free slots.

Insert the new drives in the free slots [4 and 5].

Create the RAID1 volume with the twi_cli. You may first have to rescan the bus with the ‘rescan’ command.

maint createunit c4 rraid1 p4:5

Create partition table on the new device, in this case,

sdb1 / 25G sdb2 swap 12G sdb3 /home the rest

make file systems, mount points, and mount the partitions

mke2fs -j /dev/sdb1 mke2fs -j /dev/sdb3 mkswap /dev/sdb2 mkdir -p /mnt/new/root /mnt/new/root/home mount /dev/sdb1 /mnt/new/root mount /dev/sdb3 /mnt/new/root/home

Do the initial rsync, then just before switching, quiet the system and do it again. The one bit of magic here is to preserve hard links [H], which linux systems are full of.

cd / rsync -vrpoglHDt --exclude=/proc --exclude=/sys \ --exclude=/net --exclude=/tmp --exclude=/mnt/new \ --delete . /mnt/new/root
Here’s a key for the flags used above:
-v, --verbose increase verbosity -r, --recursive recurse into directories -p, --perms preserve permissions -o, --owner preserve owner (super-user only) -g, --group preserve group -l, --links copy symlinks as symlinks -H, --hard-links preserve hard links -D same as --devices --specials --devices preserve device files (super-user only) --specials preserve special files -t, --times preserve modification times

Fix the permissions on /tmp

chmod 1777 /mnt/new/root/tmp

Write grub

grub-install --recheck --root-directory=/mnt/new/root /dev/sdb

Fix fstab so that it doesn’t use UUIDs [we can put those back after we get it booted happily off the new drives]. It’s probable that the UUIDs won’t change when we move the drives to the first two slots, but I didn’t test this.

Reboot.

manually set root=/dev/sda1 at the grub prompt

after booting, find the new uuids with ‘blkid’, and modify /etc/fstab accordingly.

run ‘update-grub’ to fix /boot/grub/grub.conf with the right uuids.

reboot again.

We also moved the two new 2T drives into slots 0 and 1, inserted a
couple of spare 2T drives and used the tw_cli utility to assign those
new drives as hot spares.

Upgrading hard drive capacity of a linux system