Performance Evaluation of Multiple TCP connections in iSCSI

TL;DR

This paper evaluates the performance of multiple TCP connections in iSCSI storage networks, proposing a Fair-TCP mechanism to improve bandwidth sharing and performance for I/O intensive workloads.

Contribution

It introduces Fair-TCP, a novel congestion sharing mechanism for multiple TCP flows in iSCSI, enhancing performance and fairness.

Findings

Fair-TCP significantly improves I/O workload performance

Multiple TCP connections can increase bandwidth but may lack fairness

Fair-TCP effectively shares congestion information across flows

Abstract

Scaling data storage is a significant concern in enterprise systems and Storage Area Networks (SANs) are deployed as a means to scale enterprise storage. SANs based on Fibre Channel have been used extensively in the last decade while iSCSI is fast becoming a serious contender due to its reduced costs and unified infrastructure. This work examines the performance of iSCSI with multiple TCP connections. Multiple TCP connections are often used to realize higher bandwidth but there may be no fairness in how bandwidth is distributed. We propose a mechanism to share congestion information across multiple flows in ``Fair-TCP'' for improved performance. Our results show that Fair-TCP significantly improves the performance for I/O intensive workloads.