A method, a non-transitory computer-readable storage medium, and a computer system for managing the placement of virtual machines in a virtual machine network are disclosed. In an embodiment, a method involves determining if at least one virtual machine in a set of virtual machines supporting a process and running on a first host computer needs to be separated from other virtual machines in the set. If at least one virtual machine needs to be separated, then at least one virtual machine is selected to be separated based on the number of memory pages changed. The selected VM is then separated from the other virtual machines in the set.