Enterprise storage remains a hot area for development and controversy. Among the hottest issues are far less interoperability among storage vendors than in other IT applications, competing transfer technologies, and an ever-growing need for larger capacities and faster data transfers. Despite the difficulty managers encounter in configuring their storage systems, the outcome for almost all new installations will be improved performance with lower ownership costs–if not immediately, at least within the first two years of operation.
A major reason for all the confusion in enterprise storage is the rapid pace of technological change. Before 2003 both Ethernet and Fibre Channel will break the 10 Gbps barrier, further complicating decisions. In addition, the advent of iSCSI (moving SCSI data over the Ethernet with IP) will add to the choices available.
By 2005, Computer Economics forecasts that Fibre Channel will be used in almost one-quarter of installations with iSCSI being used in 15 percent. The two technologies will often be combined in a hybrid approach that will accommodate both storage nearby (within the same city) as well as across the country.
Comparing Fibre Channel with iSCSI is difficult today because no real iSCSI installations exist. Therefore, the cost of iSCSI remains a conjecture. Even so, some conclusions regarding where the two technologies are headed may be drawn. Fibre Channel is expensive–usually more than equivalent Ethernet connectivity. The advantage of Fibre is that it can move the data rapidly and reliably.
The data rate for iSCSI is less predictable because of the latency built into IP. The intelligence inherent in IP, however, can be used to overcome many of these problems, so the speed at which data will move through iSCSI channels may be equivalent to Fibre Channel. For example, Edward Jones & Co. is now rolling out a storage-over-IP network to replicate 90 Tbytes of data from its St. Louis data center in Tempe, AZ, 1,500 miles away.
Concerns about security, however, will complicate the design of future Fibre Channel networks. There is little or no security designed into Fibre Channel, so protecting the stored data will require significant additions. On the other hand, advocates of iSCSI claim that existing protective methods built into IP can simply be extended to data storage.
July 2002
