A performance analysis of the iSCSI protocol

Fibre channel has long dominated the realm of storage area networks (SAN's). However, with increased development and refining, iSCSI is fast becoming an equal contender which is causing many companies to reconsider how future storage networks shall be implemented. In addition to reduced costs and a unified network infrastructure, iSCSI allows for the deployment of storage networks over a commodity internet. Moreover there are inexpensive software implementations of the iSCSI protocol that may provide compelling platforms for iSCSI deployment. This paper discusses findings of a performance study on the iSCSI protocol in four different configurations. The first two consist of iSCSI in a more commercial setting, where specialized hardware is used for the iSCSI target and two different configurations are examined for the initiator. These results are contrasted with the performance of fibre channel in a similar setting. The second two configurations focus on iSCSI deployed purely in software in both SAN and WAN environments. The performance results indicate that the iSCSI protocol can be severely limited by the implementation. This is due to either inefficient handling of the underlying network, or to not using sufficient system resources to take advantage of a network.