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One of the “iFUD” arguments that is attempting to gain currency is the notion that Fibre Channel’s days are numbered and that it only makes good sense for customers to align with a vendor that already dominates mainstream IP networking. In other words, “Don’t keep buying from those dead-end Fibre Channel vendors; join the winning team, captained by Vendor X.”
The technical substantiation to this argument is that Fibre Channel, like early LANs, is a layer two (link layer) protocol, vulnerable to broadcast storms and other upheavals. The premise is that just as IP routing displaced bridged LANs, storage networks will soon jettison traditional Fibre Channel (FC) in favor of iSCSI and IP. So customers who buy Vendor X’s Fibre Channel products today will be positioned to migrate to the new storage paradigm, whereas the unfortunates who continue to buy from traditional Fibre Channel vendors will be locked in a link layer past.
This of course begs the question of whether or not Fibre Channel is truly a dead-end technology. At the current continued rate of adoption and increasing capabilities of Fibre Channel (including 4Gbps, 8Gbps, and 10Gbps speeds), there are no signs of weakening. Unlike IP networking, Fibre Channel is a channel architecture. Storage, in data center environments, is a channel application. High performance switching and minimal protocol overhead creates the most efficient means to move large volumes of data within a local environment.
The fabric reconfiguration and link layer broadcast issues associated with Fibre Channel really only appear when the technology is pushed beyond its original design specifications. Pushing native Fibre Channel beyond metropolitan distances, for example, may create problems, but new technologies such as SAN routing with fault isolation can deal with these. For properly designed data center installations, a channel-based link layer protocol such as FCP provides the optimum plumbing for enterprise storage transactions.
The tremendous value-add for IP-based storage, and in particular iSCSI, is to further amplify the benefits that have already been demonstrated by Fibre Channel SANs. Mission-critical business applications are better served by dual-pathed 2 Gbps Fibre Channel links running through five nines (99.999%) available Fibre Channel directors and a streamlined FCP link layer protocol. But enterprises typically have hundreds (in some cases, thousands) of second-tier servers and applications that could also benefit from SAN attachment. iSCSI offers flexible and very affordable options for connecting those platforms and extending the benefits of shared storage to a much broader server population.
So instead of sounding the death knell of Fibre Channel, iSCSI is validating and enhancing the value of Fibre Channel at the core, while creating new opportunities for customers to fully maximize shared storage as a corporate asset.
What advantage does this give Vendor X? None, really, considering that all the major Fibre Channel switch vendors have both Fibre Channel and iSCSI offerings. The winning team will be comprised of those who fully understand how the two technologies can complement one another and that can demonstrate truly useful business solutions.
As a customer, I would feel uncomfortable buying Fibre Channel products from a vendor that is simultaneously declaring Fibre Channel’s demise. I would feel especially uncomfortable if the vendor’s Fibre Channel products were based on a blocking architecture and unilaterally imposed proprietary frame tagging as a kludge for poor product design. The short of it is that I would have difficulty feeling part of a winning team.