I/O Performance of an RAID-10 Style Parallel File System

Without any additional cost, all the disks on the nodes of a cluster can be connected together through CEFT-PVFS, an RAID-10 style parallel file system, to provide a multi-GB/s parallel I/O performance. I/O response time is one of the most important measures of quality of service for a client. When multiple clients submit data-intensive jobs at the same time, the response time experienced by the user is an indicator of the power of the cluster. In this paper, a queuing model is used to analyze in detail the average response time when multiple clients access CEFT-PVFS. The results reveal that response time is with a function of several operational parameters. The results show that I/O response time decreases with the increases in I/O buffer hit rate for read requests, write buffer size for write requests and the number of server nodes in the parallel file system, while the higher the I/O requests arrival rate, the longer the I/O response time. On the other hand, the collective power of a large cluster supported by CEFT-PVFS is shown to be able to sustain a steady and stable I/O response time for a relatively large range of the request arrival rate.