Abstract: A method for memory management includes in a virtual-machine monitor of a virtualization platform allocating in a guest operating system of the virtual machines guest balloon memory modules of variable memory size. Memory parameters of a given virtual machine are read. A value of a configured limit, set in the virtual-machine monitor, for the consumed memory is read. The value represents a threshold beyond which allocation of memory to the guest balloon memory module is to be performed. The threshold value is shifted from the configured limit to a lower value. A start of ballooning operations is waited for by the virtual-machine monitor. It is checked when said ballooning operations terminate. The threshold is set beyond which allocation of memory is to be performed back to the configured limit value.

Abstract: Assigning of application-hosting virtual machines to a plurality of servers inclusive of active and inactive servers in a data or calculation center is described.

Abstract: A method is disclosed for providing for a high-level local manager in each data center of a group of data centers. The high-level local manager is configured to allocate a new virtual machine or re-allocate an already running virtual machine. The high-level local managers exchange information with each other and run the same programs or processes, so that each local manager knows where the new virtual machine is to be assigned. Once determined which data center will execute the virtual machine, the method provides for a low-level local manager to assign the virtual machine to one of the servers of the data center according to a local algorithm.

Abstract: Assigning of application-hosting virtual machines to a plurality of servers inclusive of active and inactive servers in a data or calculation center is described.