Domain Level Page Sharing in Xen Virtual Machine Systems

Abstract

The memory size limits the scalability of virtual machine systems. There have been some researches about sharing identical pages among guest systems to reduce memory usage. However, they require memory overcommitment feature through swap mechanism which some virtual machines including Xen do not have. In this paper a new approach is proposed to share identical pages with designated sharing area. This approach reduces the memory usage as well as redundant I/O operations. Moreover, understanding the characteristics of certain shared pages becomes easier. The conceptional design was evaluated by simulation based on real-world applications.