On Maximizing iSCSI Throughput Using Multiple Connections with Automatic Parallelism Tuning

Abstract

In this paper, we propose an iSCSI-APT (iSCSI with automatic parallelism tuning) that maximizes iSCSI throughput in long-fat networks. In recent years, as a protocol for building SANs (Storage Area Networks), iSCSI has been attracting attention for its low cost and high compatibility with existing networking infrastructure. However, it has been known that iSCSI throughput degrades in a long-fat network. iSCSI supports a feature called multiple connections, which allows data delivery over multiple TCP connections in a single session. However, for effective utilization of the multiple connections feature, the number of multiple connections must be appropriately configured according to the network status. In this paper, we propose the iSCSI-APT that automatically adjusts the number of multiple connections according to the network status. Through experiments using our iSCSI-APT implementation, we demonstrate that iSCSI-APT operates quite effectively regardless of the network delay.