This talks about migrating the DB
This talks about performance
Forgot to mention it is Esxi 5.0 and I am looking for a best practise on that as well............
1. keep vcenter and vcenter database on a seperate virtual machine.
2. create a DRS rule to seperate the vcenter and vcenter DB VM, so they wont run on the same esxi.
3. set DRS level to Manual for both vc and vcdb VMs and Make a note on the ESXI on which its running, incase of any failure in vc or vcdb, your can easily connect to that esxi and take virtual machine console.