We want to migrate our existing BW- BPC system on SAP HANA, there are 2 BW- BPC Servers currently. 
I want to understand the proper approach for the same. means – I read somewhere that I need 2 HANA boxes individually for both, or can I have both BW servers running on a single
Instance on Hana.
If yes, do you have any supporting which can back up the assumption.
Is approach 2 possible, that is run both BW System on one DB.
If yes, please explain.