Dynamic Multipath Load Balancing Algorithm Design Based On Response Time

In FCSAN or IPSAN environment, server and storage array connects throughfiber-optic network or IP network, the server can choose different paths to sent I/O requestto storage array. When new I/O request is coming, how to choose a path and how todistribute I/Os will be a very important issue.Linux’s round-robin is relatively limited. In many applications and environments, itcan not meet the requirements of the use. It distributes simply I/Os to cach path with1000times. It doesn’t consider path’s load capacity. If the path load capacity is too small, therewill be a large amount of I/Os stuck on the path. Dynamic multipath load balancingalgorithm based on response time chooses the shortest path to distribute I/Os. If theresponse time is same, choose a path of relatively short time of service to distribute I/Os,which can calculate by relative throughput, queue I/O size and request I/O size. It caneffectively improve the utilization and I/O response speed and ensure the upper fasterfeedback. After testing, IOPS has been significantly different on each path and has aoverall improvement. Disk read speeds improve quickly, it has a few megabytes changes.The overall speed has alse been a good change. By analyzing and summarize, this articlehas achieved the intended, the test results are good.