Performance analysis of iSCSI with data center bridging suite of protocols

Storage Area Networks (SAN) are the leading storage infrastructure in modern data centers. A traditional SAN deployment relies on the Fibre Channel Protocol (FCP) over an over-engineered and expensive Fibre Channel network to provide lossless communication and predictable performance. Alternatives were proposed to reduce the deployment cost: (1)iSCSI over Ethernet, and (2) Fibre Channel over Ethernet (FCoE). The former recovers from packet losses relying on the services of TCP in the TCP/IP stack, and the latter enjoys lossless transport using the Data Center Bridging (DCB) suite of protocols. Running iSCSI over existing IP networks is desirable as it is easier to implement and maintain. However, packet losses and TCP retransmissions in best effort IP networks, tend to make the performance of iSCSI non-deterministic. In this paper, we investigate the benefits of running iSCSI over DCB enhanced Ethernet as compared to iSCSI over traditional Ethernet to overcome its performance limitations.