I need to upgrade our Zen11.2.4 to 11.3.1, to do this I first have to migrate it to new hardware because of SLES11 (the old server is too big of a mess to try and upgrade it).

I have a new server running the latest SLES 11 sp3, the old one is SLES 10 sp4.
We're running a single server instance Zen 11.2.4 (everything on 1 server, ~250 WS, sybase on the server)
What would be the way to get this done ..

Option A) Backup the old server, place the backups on the new one, turn off the old server and swap the IP/hostname of the new one to the old, install Zen11.2.4 and restore the backup.
Option B) Install new server as 2nd Primary server, sync/replicate everything over and retire the old server ? I think this will give problems with the DB because a 2nd primary server will use the DB on the original ?
Option C) Something else .. :-)

I'm guessing that if the install fails with option A, I can just turn off the new server and boot the old one back up.

Any advice / tips would be very appreciated.