A Pci Card-based Distributed Cache Is Applied Research

With the development of network technology, large-scale application of Gigabit Ethernet is an inevitable trend of Internet development. Network transfer rate will no longer be the bottleneck of data transmission. The performance of the server will be the key issues of the network applications. Similar to file server, Streaming Media Server is used to send local files to clients via network. This type of server will inevitably produce a large number of I / O operations. And Disk I / O rate will largely affect the performance of the server. Therefore, caching mechanisms have been introduced to improve system I/O performance such as page cache in Linux kernel which cache the data recently read into the memory so that next access the data directly from the memory rather than disk. Because memory data transfer rate is faster than the disk data transfer rate, it improves the system performance.Because of constrains of memory capacity and in order to improve the I/O performance of the server, a new cache system based on the IXP425 PCI card is introduced into linux-2.6.21 kernel to expand the cache hierarchy and improve the system I/O performance, which is called PCI Cache. The PCI Cache increases the cache capacity of system and reduces the access of disk. So it extends disk life time and system I / O performance.Firstly, the thesis introduces some cache and distributed systems and some of their instances. Then it describes implementation of the read I/O and page cache mechanism in the linux-2.6.21 kernel. And the design and implementation of PCI Cache will be introduced next, which include introduction about the PCI card and its driver, cache management including implementation of reading and writing the cache block and the cache consistency. Finally introduce an application of this distributed cache system - low-cost streaming media server and its testing.