面向虚拟机的远程磁盘缓存  

Remote Disk Cache for Virtual Machines

作　　者：陈昊罡[1] 汪小林[1] 王振林 靳辛欣[1] 温翔[1] 罗英伟[1] 李晓明[1] 

机构地区：[1]北京大学计算机科学技术系,北京100871 [2]密西根理工大学,密西根499311295

出　　处：《计算机科学与探索》2010年第12期1073-1088,共16页Journal of Frontiers of Computer Science and Technology

基　　金：国家自然科学基金No.90718028;60873052;国家重点基础研究发展规划(973)No.2007CB310900;国家高技术研究发展计划(863)No.2008AA01Z112;教育部-英特尔信息技术专项科研基金No.MOE-INTEL-08-09~~

摘　　要：在虚拟机(virtual machine)系统中,随着虚拟机数量和应用程序需求的不断增长,内存容量已经成为应用程序性能的主要瓶颈。为了提升内存密集型和I/O密集型程序的页面交换性能,提出了虚拟机的远程磁盘缓存机制REMOCA,它允许运行在一台物理主机上的虚拟机将其他物理主机的内存作为其二级磁盘缓存。由于网络传输延迟远远小于磁盘访问,用网络传输代替磁盘访问就能够有效地降低虚拟机的平均磁盘访问延迟。REMOCA的目标就要尽可能地减少磁盘访问。REMOCA运行在虚拟机管理器中,其基本工作原理是截获并处理虚拟机的页面淘汰、磁盘访问等事件。REMOCA能够与现有的虚拟机内存管理机制(如气球技术、影子缓存)相结合,从而提供更加灵活的内存资源管理策略。实验数据表明,REMOCA能有效地降低页面抖动对虚拟机性能的影响,并在很大程度上提升虚拟机中I/O密集型应用的性能。In virtual machine systems, with the increase in the number of virtual machines and the demands of applications, the main memory is becoming a bottleneck of application performance. To improve paging performance for memory-intensive or I/O-intensive workloads, this paper proposes the remote disk cache （REMOCA）, which allows a virtual machine to use the memory resource on other physical machines as its cache between its virtual memory and virtual disk devices. The goal of REMOCA is to reduce disk access, which is much slower than transferring memory pages over modem interconnect networks. As a result, the average disk I/O latency can be improved. REMOCA is implemented within the virtual machine monitor, by intercepting guest events such as page evictions and disk accesses. This design is transparent to the applications, and is compatible with existing techniques like ballooning and ghost buffer. Moreover, a combination of them can provide a more flexible resource management policy.The experimental results show that REMOCA can efficiently alleviate the impact of thrashing behavior, and also significantly improve the performance for real-world I/O-intensive applications.

关 键 词：虚拟机管理器 虚拟机监视器 远程磁盘缓存 内存服务器 

分 类 号：TP315[自动化与计算机技术—计算机软件与理论]