aside: I suggest people use ddrescue instead of cat.
1. It provides flashing lights showing activity and speed (cf the cat command which just sits there for a few hours and then returns you to a prompt. Hmm)
2. It retries any bad sectors it may come across rather than just stopping (which is why it's better than dd)
3. It should be faster than either of them.

Downside: it may require a rescue disk like RIP:
http://www.tux.org/pub/people/kent-robotti/looplinux/rip/
Upside: RIP is small to download.

As you install the disks, I'd suggest noting down the serial numbers (just the last 4 digits is OK) and then using
smartctl -i /dev/sda
to show the serial number of /dev/sda
This gives you a lot more confidence that you know which drive is which.
Also, don't assume that it will be the same in different distributions or OS versions. Sometimes the drives appear in a different order so the serial number check is always good.


Stu; the copy won't make use of all the disk space straight away but that's OK, growing it later is fine.