存储区域网络中路径容错及负载均衡的研究

Research on Fault Tolerant Paths and Load Balancing for Storage Area Networks

为利用存储区域网络的冗余路径,在主机上加入驱动程序对逻辑单元(LUN)的输入/输出请求进行截获。在故障路径上的I/O请求失败后,由驱动程序在正常路径上重新执行。路径失败时I/O请求直接发送给HBA驱动程序,避免了磁盘驱动程序中的无效重试过程,缩短了故障切换时间。I/O请求被分配到多条路径上,提高了主机的吞吐能力,缩短了I/O平均响应时间。

To utilize the redundant paths in storage area networks, a storage path driver （SPD） is proposed and implemented to hook I/O requests bound for the logical units. The SPD driver routes all failed I/O requests on the failed path through survival paths. The failover time is reduced by skipping the retry operations of the disk device driver. I/O requests of the logical units are distributed among all physical paths, the host load is balanced on these parallel paths to improve the I/O performance, including increasing the I/O throughput and shortening the average I/O response time.