Facing impending competition, Fibre Channel supporters cite improved interoperability, faster performance, and lower prices.
By Zachary Shess
Fibre Channel stands as the entrenched incumbent among storage area network (SAN) protocols. However, the Fibre Channel community faces eventual competition from alternatives such as iSCSI- based IP SANs, whose supporters are quick to point out Fibre Channel's shortcomings.
In response, Fibre Channel vendors continue to make steady progress on the interoperability, performance, and pricing fronts, according to proponents. End users and analysts appear to agree, as Fibre Channel SAN adoption rates are forecasted to climb steadily despite a cool economy.
Research firms such as International Data Corp. (IDC) predict that Fibre Channel will continue to dominate the SAN market through 2005. However, iSCSI and, to a far lesser degree, InfiniBand, are expected to chip away at Fibre Channel's dominance. IDC predicts that by year-end, Fibre Channel will account for more than 99% of SAN switch port shipments. But by 2005, that percentage may drop to about 76%, with Ethernet/IP SAN switch ports accounting for 17% of port shipments. InfiniBand is expected to garner 6.6% of the market in 2005 (see table).
"If you want to install a SAN, the path of least resistance is Fibre Channel, and that will be true for the foreseeable future," claims Tom Hammond-Doel, a Fibre Channel Industry Association (FCIA) board member and director of product marketing at Vixel.
However, even its staunchest supporters admit that the path to Fibre Channel adoption has been bumpy. The protocol has struggled with interoperability, complexity, and price issues that kept adoption rates well below what was expected in the late 1990s. However, with interoperability improving and prices falling, more and increasingly diverse organizations are implementing Fibre Channel to build out their storage networking infrastructures.
SANmark fosters interoperability
With the exception of price, the most significant gating factor to adoption of Fibre Channel SANs has been interoperability issues among devices from different vendors, especially at the switch and management software layers, which has often made deploying Fibre Channel a complex proposition. In response, industry "plugfests" were created to test interoperability. Plugfests continue today, but Fibre Channel proponents, including the FCIA, admit that process alone is insufficient.
In response, FCIA launched the SANmark qualification program in August 2000. SANmark is a set of test suites that vendors can run to determine how Fibre Channel devices and application program-ming interfaces (APIs) comply with specifications laid out by the ANSI T11 committee. To earn SANmark qualification, a device must pass interoperability tests with other products.
FCIA officials claim that programs like SANmark have given Fibre Channel an interoperability lead over emerging storage protocols that may still require significant testing time. To date, more than 30 companies have qualified 75 products under the SANmark program.
"We expect to see iSCSI deployments, but we challenge the notion of iSCSI proponents who believe it's a superior technology that will supplant Fibre Channel and solve all your storage problems. We've heard those claims before," says Marc Oswald, an FCIA board member and director of technology alliances at Brocade Communications.
Over the past several months, FCIA member companies have focused on defining a test suite for fabric switch services, including a test to qualify switch-to-switch communications. FCIA members have also begun to tackle software management tools and APIs for host bus adapters (HBAs).
"Those interfaces provide a consistent set of information up to management software. If HBA vendors provide the APIs, a broad range of management tools can access their cards," says David Allen, an FCIA board member and senior product manager at LSI Logic.
Fibre Channel vendors and industry analysts believe the complexities associated with implementing Fibre Channel SANs cannot be blamed on the protocol itself. "The real issue is that you're going from an easy-to-manage, direct-attached storage environment to an infrastructure where storage is shared," says Oswald, "and storage administrators have to think very differently."
"A lot of progress on interoperability has occurred in the last year or so, and I think end users would agree," says Eric Sheppard, a senior research analyst with IDC, in Framingham, MA. "However, there are still non-interoperability issues between competitors in certain areas of the SAN market. That hasn't changed."
Moving to 2Gbps
Considerable progress has also been made on the performance front. Staying one step ahead of Gigabit Ethernet, most Fibre Channel devices such as HBAs, switches, directors, and disk arrays now support second-generation, 2Gbps speed at about the same price as 1Gbps products.
The move to 2Gbps is a boon to industries such as medical imaging and film/video, which require high-speed throughput. But opinions are mixed as to whether the performance increase will generate a significant upswing in Fibre Channel adoption.
"The primary driver for 2Gbps is to keep up with the faster streaming media rates coming off the disk drives," says Allen, "especially if you're on a shared bus such as Fibre Channel. This applies to all applications because everyone wants to access his data quickly."
While not arguing that point, analysts contend that most end users today either don't have time to consider anotheralbeit fasterround of Fibre Channel devices or simply aren't using up existing bandwidth. IDC estimates that less than 5% of the Fibre Channel switch ports shipped have been 2Gbps.
"End users have spent a great deal of money and time making sure SANs work properly, and many of them won't want to introduce 2Gbps products into those environments right away," says IDC's Sheppard.
"Having more bandwidth is always better, but in reality small-block I/O applications take up nowhere near 1Gbps," says Steve Duplessie, senior analyst at the Enterprise Storage Group, in Milford, MA. "But that's not to say that users wouldn't want that speed between switches or to a big backbone." Duplessie also acknowledges that large-block applications such as imaging and multimedia do in fact require 2Gbps speeds.
Despite its benefits, many organizations have lacked the capital to bankroll a Fibre Channel SAN. Vendors have responded in recent months with technology- and marketing-driven initiatives to help drive down SAN pricing. For example, several vendors such as Agilent, LSI Logic, and QLogic are enabling Fibre Channel functionality on the host motherboard, as opposed to requiring a separate card or HBA. This type of cost reduction is just the beginning, according to Duplessie, who anticipates Fibre Channel switches eventually being integrated on PCI cards.
From a marketing perspective, the FCIA and its member companies have made recent announcements focused on "SAN starter kits," consisting of Fibre Channel devices and software at more affordable prices. In February, 35 storage companiesincluding RAID, HBA, and software vendorsjoined an initiative promising to deliver low-end SANs for starting prices as low as $50,000. FCIA officials hope that lower prices will entice smaller organizations to implement SANs.
Results from a survey of 73 companies by RBC Capital Markets and CompTIA appear to support the FCIA's claim that Fibre Channel SANs will become increasingly prevalent in small and midrange markets, while remaining dominant at the enterprise and Fortune 500 levels. Over the next two years, the percentage of small ($50 million to $250 million) and medium-sized ($250 million to $1 billion) organizations deploying SANs will increase from about 15% and 25%, respectively, to 31% and 45%. (For more information on this survey, see "Fastest SAN growth expected in mid-tier enterprises," InfoStor, March 2002, p. 1.)
Overcoming Distance Limitations
Another sign of Fibre Channel's maturity is the development of the Fibre Channel over IP (FCIP) protocol, which encapsulates Fibre Channel and tunnels it over IP networks. By leveraging the longer distance capabilities of IP, FCIP can facilitate WAN connectivity between SANs (see "Going the distance with IP storage over WANs," InfoStor, March 2002, p. 23), enabling an organization's SAN islands to be linked beyond Fibre Channel's 10km distance limitation.
As September 11 tragically generated even more interest in backup and recovery, more IT managers and CIOs are considering storage technologies that help ensure data protection. For those organizations with Fibre Channel SANs in data centers located around the country, standards such as FCIP will enable them to move data between SAN islands while keeping their existing fabric services and management tools intact.
Looking ahead, Fibre Channel proponents are optimistic about continued growth as the protocol continues to mature and products become more standardized and less expensive.
Specifically, through its SANmark program, the FCIA plans to develop additional fabric services specifications, including system security policies, cluster functionality, diagnostics, and multi-path I/O and fail-over policies.
And as performance continues to improve beyond 2Gbps, end users in years to come may be able to enjoy bandwidth up to 10Gbps.
Zachary Shess has covered the storage industry since 1995 as an analyst and former senior editor at InfoStor. He can be reached at firstname.lastname@example.org.
IP over Fibre Channel: The protocol that gets no respect
By Jeff White and Bill Peldzus
Emerging protocols such as iSCSI, FCIP, and iFCP have received considerable attention, but this has not been the case for IP over Fibre Channel (IPFC), an established standard. IPFC is the encapsulation of IP packets in Fibre Channel frames and is intended to facilitate IP communication over a Fibre Channel network.
Fibre Channel is a networking architecture that supports the transport of multiple upper-layer protocols. The most common transport over Fibre Channel is SCSI, but it also supports others such as TCP/IP, ESCON, ATM, and HIPPI. Fibre Channel is a high-bandwidth, high-reliability, low-latency, low-overhead networking architecture that supports dedicated bandwidth, guaranteed order delivery, and datagram capabilities. In addition, current Fibre Channel speeds (2Gbps) will migrate to 10 Gbps. Given all of its capabilities and performance characteristics, it is puzzling that there is such a dearth of support for IPFC.
There are a number of applications for IPFC, with high-availability (such as clustering) and high-performance computing being two of the more obvious choices.
In a high-availability environment, using a Fibre Channel storage area network (SAN) as a TCP/IP heartbeat network would be an obvious win. In a high-availability environment, one or more dedicated Ethernet heartbeat networks are usually installed to validate and ensure the cluster is online and functioning. Using a Fibre Channel SAN as a heartbeat network also guarantees that the host is communicating with the SAN, as well as with its own storage subsystems. If a cluster member cannot communicate with the SAN, it's most likely having severe problems, and a cluster reconfiguration is probably warranted.
In a high-performance computing environment, the ability to achieve guaranteed delivery of packets allows network designers to use something other than TCP to guarantee proper delivery of data. One option is to use User Datagram Protocol (UDP) and rely on Fibre Channel for delivery. Using UDP can avoid some of the windowing and back-off problems that may occur with TCP at very high speeds. Another advantage is the ability to move very large datagrams in a single packet through an IPFC network. Fibre Channel discovery, fast reconfiguration, and scalability are other features that would benefit this application.
Another environment ripe for an IPFC infrastructure would be clustered/shared file systems. In most clustered/shared file systems, metadata is managed and routed through a TCP/IP network, typically Ethernet, while the actual data is routed through a SAN. Moving metadata communication and management onto a SAN is another option for reducing complexity and increasing reliability.
So why hasn't IPFC caught on in the industry? In talking with OEMs and large business customers, Imation Storage Professional Services sees a "Catch-22" situation for both parties. OEMs are not interested in investing in IPFC because their customers are not expressing real interest. Prospective customers are not expressing interest because of a lack of products available for IPFC and therefore are not recognizing the potential solutions it provides to existing problems. A classic example of this is the lack of products that can route IP between Fibre Channel and other networks such as Gigabit Ethernet. Clearly, all of the IP storage hardware products with Fibre Channel and Gigabit Ethernet interfaces only need minimal software and/or firmware improvements to add this functionality.
In summary, the Fibre Channel industry should look to expand its horizons to include not only SCSI, but also IPand give IPFC some of the respect that it deserves.
Jeff White is a senior storage engineer and Bill Peldzus is storage consulting marketing manager in Imation's Storage Professional Services division (www.imation.com/storageconsulting) in Oakdale, MN.