The gist of the challenge:
I have a IBM ppc hosting virtual clients running RH AS 4 update 6.
I need to migrate these from Hitachi SAN (the clients boot off of the SAN) to EMC SAN.
Currently the clients have LVM installed, but not used for any of the filesystems.
Need to present new EMC Luns to the clients (IBM is helping with this) and make a bootable mirror of the Hitachi Luns onto the EMC Luns.

How can this be done?
Some ideas I have come across:
DD the filesystems from Hitachi Luns to the EMC Luns at the client OS level. This takes a long time to perform, might be too long as under a time crunch.
Install Veritas Volume manager to help facilitate the mirroring process (depending on how long this takes, under a time crunch).

Any help in this area is greatly appreciated, as well as any caveats to watch for.

Thanks!