An SRP Target Mode to Improve Read Performance of SRP-Based IB-SANs

SCSI RDMA Protocol (SRP) is used to build high performance Storage Area Networks (SANs) over InfiniBand, or SRP-based IB-SANs for short. The I/O read performance is critical for many read dominant applications, such as multimedia, remote sensing, data backup, etc. However, if I/O accesses focus on a specific storage device of an IB-SAN, the local I/O performance of single device could become the bottleneck, leaving the network performance under utilized. In this paper, we propose an SRP target mode called Target Disk Cache Assisted (tDCA) mode, which explores the file readahead feature and page cache of Linux to tackle the performance gap between storage devices and network. Experimental results show that this strategy improves the read performance in terms of throughput which is increased significantly for both random read with good locality and sequential read.