Memory resource management in VMware ESX server

VMware ESX Server is a thin software layer designed to multiplex hardware resources efficiently among virtual ma-chines running unmodified commodity operating systems. This paper introduces several novel ESX Server mechanisms and policies for managing memory. A ballooning technique reclaims the pages considered least valuable by the operat-ing system running in a virtual machine. An idle memory tax achieves efficient memory utilization while maintaining per-formance isolation guarantees. Content-based page sharing and hot I/O page remapping exploit transparent page remap-ping to eliminate redundancy and reduce copying overheads. These techniques are combined to efficiently support virtual machine workloads that overcommit memory.