Trace system of iSCSI storage access and performance improvement

Abstract

In this paper, an IP-SAN access trace method is proposed and its evaluation is presented. IP-SAN and iSCSI are expected to remedy problems of Fibre Channel (FC)-based SAN. Servers and storage cooperatively work with communications through TCP/IP in IP-SAN system, thus an integrated analysis of both sides is considered to be significant for achieving better performance. Our system can precisely point out the cause of performance degradation when IP-SAN is used for a remote storage access. In experiment of parallel iSCSI access in a high-latency network, the total performance is limited by a parameter in an implementation of the SCSI layer in the iSCSI protocol stack. Based on the result obtained with our IP-SAN access trace system, the parameter in the layer is modified. As a result, more than 30 times performance improvement is achieved compared with the default value case. Thus it is effective to monitor all the layers in the iSCSI protocol stack and execute an integrated analysis, using our system. © Springer-Verlag Berlin Heidelberg 2005.