After a sluggish start, the pace of adoption for the 8 Gbps Fibre Channel (FC) protocol is poised to ratchet up...
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now that the supporting host bus adapters (HBAs), switches and storage arrays are gaining critical mass, prices are dropping and the improving economy is spurring IT shops to reopen their wallets.
Of the roughly 1.5 million FC switch ports that shipped in the third quarter of last year, approximately two-thirds were 8 Gbps and the other third was 4 Gbps, according to Seamus Crehan, a vice president at Dell'Oro Group Inc., a Redwood City, Calif.-based market research firm that tracks the networking and telecommunications industries. The prior quarter, 8 Gbps vaulted to the majority of the FC switch-side port shipments for the first time since the technology started shipping, he noted.
Meanwhile, shipments of 8 Gbps HBAs doubled between the second and the third quarters of last year, to more than 120,000, on the heels of a doubling between the first and second quarters, Crehan said.
That trend coincided with the emergence of servers based on Intel Corp.'s Xeon 5500 processors (code named Nehalem), which enable substantially higher server I/O throughput and provide the potential to run more virtual machines (VMs) per server. Crehan said the new Intel-based servers, with 8 Gbps HBAs, are able to handle more bandwidth, and increasing levels of server virtualization drive the need for it.
But server virtualization can also have a diametrically opposite effect on 8 Gbps adoption. On one hand, the consolidation of physical servers down to a single one running 10 or more VMs can boost server utilization and fuel demand for more bandwidth. Plus, next-generation servers pave the way for more VMs per server. On the other hand, it frees up switch ports and leaves companies with excess inventory. If they don't have other applications that need the extra bandwidth, they might hold off on implementing the 8 Gbps FC protocol.
Robert Stevenson, managing director of storage technology at The InfoPro Inc., a New York City research firm that surveys Fortune 1000 companies, recalled one large company telling him that it hoped to reduce its switch port count from 40,000 to 30,000 this year as a result of server consolidation. In the absence of applications demanding 8 Gbps, switches at the end of their depreciation schedule or operational support problems, it's difficult to ask management for 5,000 new 8 Gbps switch ports when there are plenty of free 4 Gbps ports, Stevenson said.
"It's harder to say, 'Look I have to buy 8 Gig because I'm running out of ports," he said.
Adoption rate of 8 Gbps versus 4 Gbps has been slow
So far, the adoption rate of 8 Gbps has been slower than the shift from 2 Gbps FC to 4 Gbps, according to Stevenson. He pointed to surveys done four years ago that show 17% of the Fortune 1000 sample group using 4 Gbps technology, and another 53% with plans to adopt it. Last year's fourth-quarter survey, by contrast, showed that 14% used 8 Gbps FC technology, but only an additional 24% planned to adopt it, and 62% had no plans at all for it.
Part of the reason for slower adoption is economic. An upgrade from 2 Gbps to 4 Gbps didn't include much of a price premium because switches and HBAs used the same small form-factor pluggable (SFP) transceivers, while the jump to 8 Gbps requires new, SFP+ transceivers and a substantial price jump. Also, the overall economy has put large upgrade projects on the backburner for many organizations.
Along with the macroeconomic climate, another factor contributing to the slower adoption of 8 Gbps could be the lack of new application demand, according to Stevenson. He said that during the shift from 2 Gbps to 4 Gbps, approximately 70% of users upgraded because new applications demanded higher throughput. With 8 Gbps, existing backup applications and databases have been the top drivers among early adopters, according to InfoPro's limited feedback from early adopters.
"Without a lot of new application demand, you're doing it just to improve your backup operations, and that's still a cost center," Stevenson said.
Applications that are driving 8 Gbps: Data backup, data warehousing and HPC
Robert Passmore, a research vice president at Gartner Inc., estimated that "95% of the applications in the world" don't need 8 Gbps, with the possible exception of data backups, data warehousing, high-performance computing (HPC) or multiple-application VMware Inc. environments.
Data backups drove Ryan Perkowski, the SAN manager at a large financial institution, to purchase a pair of Brocade Communications Systems Inc. inter-link switches with three 8 Gbps ports apiece and new SFP optical transceivers for his Brocade DCX core switch. But Perkowski said he has no need for extra bandwidth with other applications, even his virtual servers, and plans to hold out for his storage vendors to provide native 8 Gbps ports before going any further.
"I prefer the entire backplane of my storage plane to support 8 Gig," he said. "I will wait it out. There's just really not a need or a push for it right now."
Some users upgrade a portion of their infrastructure to 8 Gbps for purely incidental reasons. Bill Fleury, a systems administrator at a health insurance company, noted in an e-mail interview that Hewlett-Packard (HP) Co. sent 8 Gbps FC switches when it was out of stock on 4 Gbps products. From the blades to the storage area network (SAN), everything else is 4 Gbps.
"If some day we are actually able to saturate the pipe provided by 4 Gbps equipment, then we may look at upgrading," Fleury wrote. "Otherwise, the only reason we'll move to 8 Gbps is it will eventually be all that's available from the vendors."
Users running applications that aren't pushing the limits of 4 Gbps FC might decide to delay or take a pass on 8 Gbps and, instead, weigh the merits of 10 Gigabit Ethernet (10 GbE) with network-attached storage (NAS) or iSCSI storage or possibly even Fibre Channel over Ethernet (FCoE), once the Data Center Bridging standards finalize.
"We're holding out to see what's next," admitted Ed Delgado, the storage architect at RiskMetrics Group Inc., a New York-based financial services company. "At this point, bandwidth is not a concern for us so we are not in need of the [8 Gbps] upgrade."
Delgado faced a decision in October 2008 when he purchased two Brocade 48000 blade-based director switches: 48 4Gbps ports or 24 8Gbps ports. The way he saw it, the 8 Gbps would have required more of an investment, since the company's HBAs were 2 Gbps and 4 Gbps, and at the time, its newly purchased EMC Corp. Clariion shipped at 4 Gbps. To get the full benefit of 8 Gbps, all of the components would have had to support it, or the switch would negotiate down to 4 Gbps.
"It's not just a matter of getting 8 Gigabit cards. Your arrays have to support it, too. Otherwise, what's the point?" Delgado noted. "You'd have an 8 Gigabit blade that you'd pay for, and go a year not using it at its 8 Gigabit capacity."
Delgado said the company's next major implementation project probably won't happen until 2011, and by then, he thinks he'll look at 10 GbE and possibly a move to iSCSI.
"We have 300 TB of storage. We have over 100 SAN-attached hosts, and the upfront cost and then having to redo all these hosts, for us, you're talking years. It's just such a pain," he said. "For most people, the vendors march in this brave world: Rip and replace is easy. And it's just not. In my world, an implementation like that takes a lot of time."
But Jeff Boles, senior analyst and director, validation services at Taneja Group, said his interviews with end users who have significant FC implementations show that most are looking to 8 Gbps as they wait for FCoE to mature. "If they're running into storage bottlenecks and already have an investment in Fibre Channel, they're looking toward 8 Gigabit Fibre Channel 85% of the time," he said.
Greg Schulz, founder and analyst at StorageIO Group, said one more iteration of FC can buy an end user two to four years of time. He also cautioned that it's a mistake for users to think they don't need 8 Gbps because they're barely using 4 Gbps.
"It's not all about bandwidth. It's about more I/O per second, more transactions, more work," Schulz said. "Applications that need to do more transactions, serve more files, more email messages, they're going to benefit."
Read Part 1 of our tutorial to discover why upgrading to 8 Gbps Fibre Channel for storage networks is a logical step as prices drop.
Fibre Channel SAN: 8 Gbps a logical step