I'd recommend 3, that will give you some redundancy see http://thelastpickle.com/2011/06/13/Down-For-Me/how many nodes to start with(2 ok?) ?
okay, so what should a workable VPS configuration to start with & minimum how many nodes to start with(2 ok?) ? Seriously I cannot afford the tensions of colocation setup. My hosting provider provides SSD drives with KVM virtualization.