Virtual machines are managed by obtaining software hierarchy information of a current virtual machine to be installed. Then logical memory assigned to the current virtual machine is divided into a private part and a shared part based at least in part upon existing software hierarchy information of at least one virtual machine already installed and the software hierarchy information of the current virtual machine. Then, the shared part of the logical memory is mapped to shared segments of a physical memory, wherein the shared segments are used by at least one installed virtual machine.