服务云计算的虚拟机动态迁移技术

Services Dynamic Migration of Virtual Machines for Cloud Computing

云计算作为互联网时代最新的IT运营模式，它是一种创新的信息系统（IS）的架构。虚拟化技术是云计算资源管理中最为有效的解决办法，其最引人注目和最有价值的是虚拟机实时迁移技术。该文以现有的Xen虚拟机实时迁移实现机制中的内存迁移为分析基础，以有效缩短迁移宕机时间为目的，提出Magician（魔术师）优化迁移框架。该框架是在典型Xen虚拟机的运行迁移模块中添加分层拷贝模块和内存压缩模块，并在相关模块下提出分层拷贝算法和内存压缩算法。通过测试分析．Magician优化了实时迁移实现的时间和空间复杂性，达到虚拟机迁移性能优化的目的。

As the latest IT operation model at the Internet age, cloud computing is an innovative architecture for information system （IS）. Virtualization technologies are the most effective solutions for management of cloud computing resources, where the live migration of virtual machines is the most valuable technology that have been attracting attention. In order to reduce the downtime effectively during migration, we propose in this paper a novel framework named Magician for optimization of migration based on the analysis of existing memory migration adopted in the live migration of Xen virtual machine. The framework is constructed by adding a hierarchy copy module and a memory compression module into the typical running migration of Xen virtual machine. Correspondingly, a hierarchy copy algorithm and a memory compression algorithm are presented in the framework. Test analysis shows that Magician reduces the time and space complexities of live migration, and thus optimizes the migration performances of virtual machines.