虚拟化环境下的虚拟磁盘写缓存机制研究

发布时间：2018-01-14 05:11

本文关键词：虚拟化环境下的虚拟磁盘写缓存机制研究　出处：《华中科技大学》2013年硕士论文　论文类型：学位论文

【摘要】：在虚拟化环境下，对于一些具有高可靠性需求的虚拟机，为了保证用户数据的一致性会采用写直达的磁盘写缓存策略；对于其他具有I/O性能需求的虚拟机，采用写回策略的磁盘写缓存可以确保其基本的I/O性能。在同一个虚拟化平台下，具有不同性能需求的虚拟机共享底层磁盘写缓存，因此，它们在写缓存的使用方式上存有争议。但是，在当前的虚拟化环境下，针对不同性能需求的虚拟机对磁盘写缓存使用方式上的矛盾并没有相应的解决方案。虚拟化环境下的虚拟磁盘写缓存系统(VDWB)利用计算机系统虚拟化的结构特点，实现了在同一个虚拟化平台上可靠性虚拟机和I/O性能型虚拟机在使用磁盘写缓存上的良好共存。VDWB系统首先对底层磁盘写缓存采用写直达方式，保证了上层可靠性虚拟机的数据一致性要求，然后为I/O性能型虚拟机在VMM中开辟一片内存空间作为虚拟磁盘写缓存(VDiskCache)，，通过虚拟磁盘写缓存对写数据流的缓冲作用，弥补因底层磁盘写缓存采用写直达方式而造成的I/O性能损失。虚拟机对虚拟磁盘写缓存的内部可控性，使得虚拟机根据上层应用需求的改变，可以实时的打开或关闭其相应的虚拟磁盘写缓存，来适应虚拟机在可靠性或I/O性能间的需求变化。同时设计了虚拟磁盘写缓存带宽控制算法，减小频繁的虚拟磁盘写缓存刷新对可靠性虚拟机的性能影响。实验结果表明，VDWB系统解决了对底层磁盘写缓存的使用方式上，可靠性虚拟机需要采用写直达方式，而I/O性能型虚拟机需要采用写回方式的争议问题。在确保可靠性虚拟机的数据一致性的前提下，VDWB系统保证了I/O性能型虚拟机的I/O性能，使其系统吞吐量提升了100%。
[Abstract]:In the virtualization environment, for some virtual machines with high reliability, in order to ensure the consistency of user data, write-to-write cache policy will be adopted. For other virtual machines with I / O performance requirements, disk write caching using write-back policies ensures basic I / O performance on the same virtualization platform. Virtual machines with different performance requirements share the underlying disk write cache, so their use of write cache is controversial. However, in the current virtualization environment. There is no solution to the problem of disk write cache usage for virtual machines with different performance requirements. Virtual disk write caching system (VDWB) in virtualized environment takes advantage of the structural characteristics of computer system virtualization. Implemented on the same virtualization platform reliability virtual machine and I / O performance virtual machine in using disk write cache good coexistence .VDWB system first of all the underlying disk write cache using write direct mode. The data consistency requirement of the upper reliability virtual machine is guaranteed, and then a memory space is opened up in VMM for the I / O performance virtual machine to write cache VDiskCache. Through the buffering effect of virtual disk write cache on write data stream, I / O performance loss caused by the underlying disk write cache using write direct mode is compensated, and the internal controllability of virtual disk write cache caused by virtual machine. The virtual machine can open or close the corresponding virtual disk write cache in real time according to the change of the upper application requirements. In order to adapt to the requirements of virtual machine between reliability and I / O performance, a virtual disk write buffer bandwidth control algorithm is designed to reduce the impact of frequent virtual disk write cache refresh on the reliability of virtual machine. The experimental results show that the VDWB system solves the use of the underlying disk write cache, and the reliability virtual machine needs to use write direct mode. However, I / O performance virtual machine needs to be written back. VDWB system ensures I / O performance of I / O performance virtual machine on the premise of data consistency of reliable virtual machine. Increases its system throughput by 100.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333.35

【参考文献】