Xen虚拟机块设备的访问优化技术

发布时间：2018-04-03 15:19

本文选题：虚拟机　切入点：块设备　出处：《华中科技大学》2012年硕士论文

【摘要】：服务器是信息服务业的基础设施，但当前利用率普遍偏低。虚拟化技术能够提升服务器效率，，降低管理复杂程度，在数据中心得到广泛运用。块设备是存储I/O系统中的主要外部设备，其访问性能对系统整体运行效率产生重要影响。虚拟化环境中存在大量并发访问，使块设备负担加剧，成为制约整体性能的瓶颈。为解决虚拟机块设备的访问瓶颈问题，以Linux操作系统中开源虚拟机软件Xen为对象，研究虚拟机块设备访问方式的优化方案。分析发现Xen虚拟机块设备访问过程中存在临界资源冲突、工作负载分布不均等问题。采用并行优化技术，为重要环节增加处理线程，将原单通道访问方式改进为双通道访问方式，缓解临界资源争用情况，提高工作效率。各个虚拟机的I/O需求不尽相同，在系统资源能够满足虚拟机需求总和的前提下，还需要有效的资源调度分配机制辅助系统运行。Xen虚拟机当前的虚拟块设备带宽分配机制仅实现平均分配，不能满足用户需求。通过分析虚拟块设备对带宽的不同需求情况，设计对应的有限状态机，并据此实现虚拟块设备带宽分配，使各个虚拟机能够进行虚拟块设备带宽动态调整，按需获取资源。通过对改进后的访问方式进行测试，证实相对原单通道访问方式，双通道访问方式读、写请求效率分别提高17%和14%，提升系统整体性能。带宽分配功能可以适应复杂的虚拟块设备工作环境，为特定的虚拟机提供最小带宽保护，保证其运行需求得到满足。
[Abstract]:Server is the infrastructure of information service industry, but the utilization rate is generally low.Virtualization technology can improve server efficiency, reduce management complexity, and widely used in data centers.Block device is the main external device in the storage I / O system, and its access performance has an important impact on the overall operating efficiency of the system.There are a lot of concurrent access in virtualization environment, which makes the burden of block devices increase, and becomes a bottleneck restricting the overall performance.In order to solve the bottleneck problem of accessing virtual machine block devices, the open source virtual machine software Xen in Linux operating system is taken as an object to study the optimization scheme of access mode of virtual machine block devices.It is found that there are critical resource conflicts and uneven workload distribution in the process of accessing Xen virtual machine block devices.Parallel optimization technology is used to increase processing threads for important links, and the original single-channel access mode is improved to two-channel access mode, which alleviates critical resource contention and improves work efficiency.The I / O requirements of each virtual machine are different. If the system resources can meet the total requirements of the virtual machine,An effective resource scheduling and allocation mechanism is also needed to assist the system to run. Xen virtual machine. The current virtual block device bandwidth allocation mechanism can only achieve equal allocation and can not meet the needs of users.By analyzing the different requirements of the virtual block device, the corresponding finite state machine is designed, and the bandwidth allocation of the virtual block device is realized accordingly, which enables each virtual machine to dynamically adjust the bandwidth of the virtual block device and obtain the resources on demand.Through the test of the improved access mode, it is proved that compared with the original single-channel access mode, the two-channel access mode increases the efficiency of write request by 17% and 14%, respectively, and improves the overall performance of the system.The bandwidth allocation function can adapt to the complex working environment of virtual block devices, provide minimum bandwidth protection for a specific virtual machine, and ensure that its operational requirements are met.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TP302

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