网络存储系统中I/O请求响应时间的研究

网络存储技术从很多方面改善了传统基于主机的存储系统的不足，但由于在数据存储和处理之间增加了网络，对整个I／O请求过程产生很大的影响，使得I／O性能难以准确地估计．通过对两种常用的网络存储系统——NAS和SAN的基本存储过程进行分析，提出了针对网络存储系统中I／O响应时间的性能评估模型．通过实验，发现这个模型在很大程度上能够对存储网络的性能进行评价．结果表明存储网络的性能不光和存储设备以及网络设备的物理性质有关，还和具体的负载状况密切联系．另一方面，FC(光纤通道)对负载状况的依赖性远远小于TCP／IP网络，就I／O响应速度而言，FC有更好的性能．

Study of the I/O Request Response Time in Network Storage Systems

Although the network storage technology has decreased the disadvantage of traditional storage systems based on host directed access storage, the introduction of the network layer has a strong impact on the average response time of I/O request and makes performance difficult to evaluate. In this paper, the process for two common network storage architectures, NAS (network attached storage) and SAN (storage area network), is discussed. Moreover, the evaluation model for network storage is presented. In the experiment it is found that the value that the model predicts is close to the data. The result of both the model and experiment shows that the performance of network is related not only to the physical character of the storage and network devices, but also to the workload. Moreover, the workload has less impacts on the performance of the fibre channel than on that of the TCP/IP network. Fibre channel has better performance only for I/O response rate.