异构盘阵中最优Stripe Unit Size选择技术

缓解计算机IO子系统瓶颈的有效手段是采用磁盘阵列，配置时，SUS(Stripe Unit Size)的选择对盘阵性能的影响非常关键，而以往对异构盘阵的SUS的选择研究较少，该文推导出了确定异构盘阵最优SUS的方程，具体工作如下：首先，该文采用close队列网络模型来描述异构盘阵负载；然后，从该模型推导出系统数据传输率解析表达式，根据该表达式和异构盘阵中设备的特性，可求出使传输率最大的SUS，最后，研究中进行了大量的模拟试验，模拟试验表明在并发的进程数大于10时，所推导的结论与模拟结果非常吻合。

The Optimal Stripe Unit Size of Heterogeneous Disk Array

Disk array is one of the most popular architectures to improve the performance of IO system, and its performance is governed by SUS, or Stripe Unit Size. Now disk array becomes more and more heterogeneous. There is, however, no analytical model to determine SUS of Heterogeneous Disks Array Systems. In this paper, technique for that is discussed in detail, and an analytical equation is put forward. Our work is as follows: First, we present a close queuing model to describe disk array system I/O load. Then we deduce an analytical expression to predict disk array data transfer rate in the closed model while load of each device in the system is balanced. According to the analytical expression, I/O load, and product characteristics of each device in heterogeneous disk array, OSUS (optimal stripe unit size) to let data delivering rate be maximal can be acquired easily. Finally, we carry out a large number of simulations, and results show that:1) Our conclusion has little error if the number of concurrent processors in the system is larger than 10. 2) The equation of OSUS is helpful while configuring heterogeneous disk array. If SUS is not OSUS, system will suffer from performance loss.