Server Virtualization: The Killer App By Larry Cormier, LeftHand Networks

Server virtualization implementations began in test and development organizations. Mostly in large businesses where existing fiber channel SANs were already in place. As the benefits server virtualization accelerated adoption by smaller organizations, the ease of use and affordability offered by iSCSI motivated end users to implement iSCSI SANs instead of fiber channel for storage. IT managers who are familiar with both technologies began to understand some inherent benefits from using iSCSI as storage for virtualized environments. Over half of our customers are purchasing LeftHand iSCSI SANs in conjunction with some sort of server virtualization project, when asked "why iSCSI instead of FC?" customers had a litany of reasons. I've tried to summarize their responses below.

The hardware-centric nature of Fibre Channel (FC) creates a number of problems when implementing virtual machines. In FC environments WWNs (World Wide Names) are used to uniquely identify equipment in the SAN. The WWN is an identifier tied to specific hardware such as a server HBA or a storage array. In virtualized environments, this dependency on physical hardware intensifies the complexity of managing the environment and exposes new security risks. iSCSI provides a number of advantages in virtualized environments.