Load balancing policy is set for a cluster, which includes one or more hosts that may each have different hardware parameters and available memory. The Red Hat Virtualization Manager uses a load balancing policy to determine which host in a cluster to start a virtual machine on. Load balancing policy also allows the Manager determine when to move virtual machines from over-utilized hosts to under-utilized hosts.
The load balancing process runs once every minute for each cluster in a data center. It determines which hosts are over-utilized, which are hosts under-utilized, and which are valid targets for virtual machine migration. The determination is made based on the load balancing policy set by an administrator for a given cluster. The options for load balancing policies are VM_Evenly_Distributed, Evenly_Distributed, Power_Saving, and None.