Performance analyses and optimization based on iSCSI

1 Introduction With advances in networking technology, iSCSI allows for the deployment of storage networks over a commodity internet. However providing storage services across networks increases communication costs: requests and results must be transported between iSCSI Initiator and iSCSI target 1,2]. Intensive overhead caused by network I/O limits the capacity of servers. This makes the study of iSCSI performance an import research topic. Earlier researches closely measure the perfo…

Performance analyses and optimization based on iSCSI

The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.