For IT shops that are committed to Fibre Channel (FC) storage networks, upgrading their storage area network (SAN)...
gear from 4 Gbps to 8 Gbps makes sense now that the price gap between the two is starting to close. Users can refresh the different components of their enterprise data storage infrastructures at their own pace because the newer 8 Gbps Fibre Channel is backwards-compatible. Plus, they'll gain the benefit of improving their application response times and increasing throughput over 4 Gbps to give a boost to bandwidth- or I/O-intensive applications and potentially reduce bottlenecks on their Fibre Channel SAN.
Users who are examining their upgrade options will find the piecemeal approach afforded by 8 Gbps is a plus: There's no need for a forklift update of the host bus adapters (HBAs), SAN switches and storage arrays at the same time. Users can refresh at their own pace because the latest FC technology is compatible with its earlier generations and the newer 8 Gbps gear automatically negotiates down to the slowest speed of the available components.
The 8 Gbps technology's ability to improve response time and increase throughput on storage networks is advantageous especially for I/O- or bandwidth-intensive applications such as backup, data analysis, database and server virtualization. The higher bandwidth can also help when used in connection with performance-boosting solid-state drives (SSDs).
Early 8 Gbps Fibre Channel SAN adopters
Yet many of the early adopters of 8 Gbps for a Fibre Channel SAN didn't deliberately plan from the outset to make the upgrade. For instance, when Los Angeles-based Shopzilla Inc., which hosts an online comparison-shopping service for consumers, needed new servers for its databases in late summer, its supplier, Dell Inc., quoted the price with 8 Gbps HBAs from QLogic Corp.
Burzin Engineer, Shopzilla's vice president of technology, hadn't considered 8 Gbps at the time, but he decided to do his homework on the viability of the technology. He soon learned that 8 Gbps was not only a realistic option but that he could move to 8 Gbps with a subsequent purchase of QLogic's SANbox 9000 series director-class switches in October.
"At that point, it did not make sense to buy 4 Gig when the price on 8 Gig was only 20% more," Engineer said.
Industry-wide, the difference in the average price of 8 Gbps Fibre Channel switch ports and 4 Gbps FC switch ports was 36% during the third quarter of last year, according to Seamus Crehan, a vice president at Dell'Oro Group Inc., a Redwood City, Calif., market research firm that tracks the networking and telecommunications industries. The prior year, the differential was 54%, he noted.
The variance in the average price of 8 Gbps versus 4 Gbps HBAs in standalone servers (which factors in the cost of small form-factor pluggable optical transceivers or SFPs) was 44% in the third quarter of 2009 and 50% in 2008, according to Crehan. But the gap was far lower for the average price of HBAs in blade servers, known as mezzanine cards, which have no SFP optics, at just 13%, he said.
The cost differential can be lower, of course, for any given Fibre Channel SAN product line. Emulex Corp.'s LightPulse LPe12000 single-port 8 Gbps FC HBA, for instance, sells for $797, while its LPe11000 single-port 4Gbps FC HBA is $780. Throwing the pattern totally out of whack, the LPe12002 dual-port 8 Gbps FC HBA actually is priced lower ($1,180) than the LPe11002 dual-port 4 Gbps FC HBA, which sells for $1,195.
"What traditionally happens is that the new bandwidth host bus adapters become available, and vendors price them very aggressively," said Robert Passmore, a research vice president at Gartner Inc. "When people refresh their servers and buy new adapters, they look at what's available, and the 8 Gig looks like a really good deal. No one pulls adapters out of existing servers."
If the pricing model has historically driven the transition to higher FC bandwidth with HBAs, performance has compelled the shift with the switches and storage arrays, according to Passmore. But users need to justify the business case because 4 Gbps is often adequate for most of their applications.
Among its FC-based applications, Shopzilla's Oracle Corp. data warehouse could potentially benefit the most from the improved performance and throughput that 8 Gbps FC would bring to storage networks. Instead, Shopzilla's 8 Gbps FC HBAs and switches currently negotiate down to 4 Gbps, since the company hasn't transitioned to the higher bandwidth on its storage arrays, which are just starting to add or promote support for 8 Gbps.
"Storage isn't a trivial cost, so I won't deliberately get it on the storage," Shopzilla's Engineer said. "But I have some storage that's end of life, and when I replace that, I will make sure I get 8 Gig."
Read the next part of this tutorial to find out why the adoption of 8 Gbps Fibre Channel is expected to soar this year after a sluggish start.