I have to upgrade the esx hosts from 5.1 to 5.5. I want to know how to transfer all the esx hosts from one vcenter to other. Also please update if any precautions to be taken, I think after upgrading them the transfer will be done. Should I keep any thing off or in maintenance. Should i do any thing remove from inventory. How will I realise to which datastore the esx host has gone after transfer. What files i have to keep in mind.