I am going to dist-upgrade my 10.10 installation to 11.04, but as precaution, I would like to replicate my existing installation onto another hard disk and perform the dist-upgrade there.

When I am in booted into my current 10.10 installation, the hard disk (MBR, 4GB) is partitioned as such:

/dev/sda1 - /boot
/dev/sda2 - swap
/dev/sda3 - /

I have an empty hard disk (MBR, 10GB) connected to the PC, and I partitioned to have a similar layout.

/dev/sdb1 - /boot
/dev/sdb2 - swap
/dev/sdb3 - /

Since the 2 HDDs are of different sizes, I made /dev/sdb3 larger.

My question is: what is the easiest way to create a backup of my current working Ubuntu onto my secondary hard disk?

I hope to perform the backup while booted into my existing 10.10 system; or I have no other choices but to boot from a LiveCD (e.g. Clonezilla) for backup?

Thank you!