Hierarchical memory resource groups in the ESX Server

Modern operating systems specialize in partitioning the physical compute resources of a computer among software applications. Effective partitioning of physical resources enables multiple applications to securely execute on the same physical machine while maintaining performance isolation. In a virtualized environment, a hypervisor partitions physical resources, among virtual machines. This enables virtual machines to securely execute on the same machine without affecting one another. VMware R ©’s ESX R © Server is a hypervisor that provides controls for partitioning memory and CPU resources among virtual machines. ESX implements a hierarchical partitioning of memory and CPU resources using resource groups. Resources are hierarchically partitioned based on their placement in a tree structure. Resource attributes such as reservation, limit and shares provide users with fine-grained partitioning controls. Hierarchical memory resource groups are a powerful tool enabling the partitioning of the physical memory resource of a computer. This enables fine-grained partitioning of compute memory among virtual machines in the datacenter. Partitioning can be deployed by a user or by automated datacenter management software. This article describes the memory partitioning scheme of ESX, provides examples to demonstrate its use and empirically evaluates its effectiveness. General Terms memory management, memory partition, memory resource groups