However, NetWare and Linux environments are also becoming popular for iSCSI, and solutions for small RISC servers running Unix are just starting to emerge.

"The driving force behind a transition from DAS (direct-attached storage) to an IP SAN is often high data growth and the need for operations efficiency. In these circumstances the legacy DAS environment becomes increasingly complex; backup/restore operations become increasingly unreliable, and the storage environment is unable to support the demands of the business," Dale said.

Since iSCSI is a SAN protocol, it was initially seen as an adjunct to Fibre Channel SANs.

"It was usually characterized as a less-capable technology that would connect stranded servers into the corporate SAN. On the other side of this argument were iSCSI proponents who viewed it as a disruptive technology that would render Fibre Channel obsolete as a SAN interconnect. The reality lies somewhere between these extreme perspectives," Dale said.

To date, iSCSI and FCP (the Fibre Channel SAN protocol) have often turned out to be complementary technologies -- each having a distinct place in the IT infrastructure as a SAN alternative to DAS. Fibre Channel generally provides high performance and high availability for mission-critical applications, usually in the corporate data center. In contrast, iSCSI has generally been used to provide SANs for business applications in smaller regional or departmental data centers.