一种基于磁盘介质的网络存储系统缓存

随着计算规模越来越大,网络存储系统应用领域越来越广泛,对网络存储系统I/O性能要求也越来越高.在存储系统高负载的情况下,采用低速介质在客户机和网络存储系统的I/O路径上作为数据缓存也变得具有实际的意义.设计并实现了一种基于磁盘介质的存储系统块一级的缓存原型D-Cache.采用两级结构对磁盘缓存进行管理,并提出了相应的基于块一级的两级缓存管理算法.该管理算法有效地解决了因磁盘介质响应速度慢而带来的磁盘缓存管理难题,并通过位图的使用消除了磁盘缓存写Miss时的Copy on Write开销.原型系统的测试结果表明,在存储服务器高负载的情况下,缓存系统能够有效地提高系统的整体性能.

Cache System Based on Disk Media for Network Storage

With the dramatic increase in the scale of computing, the applications of network storage systems become wider, and the requirements for their I/O performance are also higher. Now with I/O heavy loaded, it becomes meaningful to cache data by using low-speed media in the I/O path between the client and network storage systems. In this paper, a cache system prototype D-Cache is designed and implemented based on disk media at block level for storage system. A two-level structure is adopted to manage disk cache and a corresponding cache management algorithm is provided for it at block level. The algorithm effectively solves the management problem of disk cache brought by the low-speed characteristic of disk media. By the use of bitmap, the cache management algorithm also eliminates the overhead of Copy on Write operations caused by write miss of disk cache. Experimental results show that the prototype can efficiently improve the overall performance for storage system with I/O heavy loaded.