iSCSI SAN finally proves worthy alternative to Fibre Channel SAN for the mainstream

iSCSI SAN use is growing while Fibre Channel SAN sales decline. iSCSI SAN use is fueled by cost advantages, ease of management and its performance with virtual servers.

After years of questions over its performance, iSCSI storage-area networks (iSCSI SANs) proved recession-proof in 2009 by growing while the overall networked storage market shrunk. Analysts predict the growth will accelerate in coming years.

Framingham, Mass.-based IDC's most recent storage tracker numbers showed iSCSI SAN revenue grew 25% in the third quarter of 2009 compared with the same quarter in 2008, while overall storage declined 7.6%. The first and second quarters of 2009 also showed increases for iSCSI and declines for the overall storage market, and iSCSI grew to 17% of the total networked storage market in the third quarter, according to IDC. The company also said that iSCSI has grown from 6% of the networked storage market in 2007 to 13% for the first three quarters of 2009, while Fibre Channel (FC) has slipped from 72% to 61% over that span.

Survey results released by Milford, Mass.-based Enterprise Strategy Group (ESG) this month said 28% of U.S. businesses now use iSCSI SANs, "marking the technology's transition from intriguing ingénue to mainstream storage solution." Of the 1,500 respondents to the ESG survey, an additional 24% said they will use iSCSI.

For more on iSCSI:
iSCSI SANs in a virtual server environment: Five best practices

iSCSI storage system implemented by University of Alaska Fairbanks

Factors in iSCSI SAN growth

iSCSI is cheaper to use and easier to manage than a Fibre Channel SAN, which requires special switches and expertise. Still, it took years for iSCSI to pick up enough users to overcome the stigma that its performance lagged behind that of Fibre Channel. The technology received a big boost in 2008 when Dell Inc. acquired iSCSI vendor EqualLogic Corp. for $1.4 billion and Hewlett-Packard (HP) Co. bought iSCSI SAN player LeftHand Networks for $360 million. That put the two biggest standalone iSCSI SAN platforms in the hands of large storage/server vendors.

Server virtualization has also contributed to iSCSI's growth. Many of the advantages of virtual servers come from having networked storage, and these servers already have Ethernet connections. Another boost is the rise of multiprotocol, or unified, storage systems that offer iSCSI and network-attached storage (NAS) for block and file storage in the same box.

The impending rise of 10 Gigabit Ethernet (10 GbE) and the advent of Fibre Channel over Ethernet (FCoE) down the road will change the dynamic for iSCSI, likely for better in some ways and for worse in others.

"It's not so much that performance has gotten better, but there's more recognition that performance is good," said Andrew Reichman, senior analyst at Cambridge, Mass.-based Forrester Research, of iSCSI. "Storage buyers are conservative, but there are now enough reference customers to point to successful implementations."

Reichman said besides the lower cost of switching for iSCSI than Fibre Channel, iSCSI has ridden the wave of VMware by getting behind the technology a few years ago, and has benefitted from Microsoft pushing it for SQL and Exchange.

Although traditionally found in lower-end systems, iSCSI use rose across the board last year, said Natalya Yezhkova, a research manager at IDC.

"We saw iSCSI pretty much everywhere: the midrange, enterprise and low end," she said. "The basic premise of iSCSI is ease of use and price, and now it has functionality it didn't have. Data protection and enterprise features make iSCSI an alternative for Fibre Channel even for enterprises."

In fact, the ESG survey shows that enterprises have an even greater commitment to iSCSI than midmarket companies, with 61% of large enterprises (20,000-plus employees) using or planning to use iSCSI compared with 47% of midmarket businesses.

Giants get behind iSCSI

iSCSI pioneer EqualLogic had enough success to prepare for an IPO by late 2007, but Dell bought the vendor and then threw its marketing weight behind the EqualLogic PS iSCSI platform.

Praveen Asthana, Dell's vice president of enterprise storage and networking, said the time was right for iSCSI. "People were over-bullish on iSCSI at one time," he said. "It was supposed to take over the world five years ago. It never used to meet analyst expectations, but now it's exceeding analysts' forecasts."

Asthana said server virtualization has been a huge boost for iSCSI, and the poor economy has helped. "The economy tanked, and with iSCSI cheaper than Fibre Channel, people started saying, 'This works just as well, let's start deploying it,'" he said.

Although HP and Dell also sell Fibre Channel SANs, Lee Johns, HP's director of marketing for unified storage, said iSCSI is an especially good fit for those vendors because of their large server business.

"Now you've got people like HP and Dell in the market who have sold most of the virtualized servers, and people who are buying them are on the server side," Johns said. "When they look at the cost of deploying iSCSI, it becomes attractive. And they can leverage their experience in Ethernet networking."

Johns said a big part of recent iSCSI-related business has been organizations that have not had FC SANs.

"First-time SAN users are definitely more likely to go with iSCSI," he said. "They don't have to invest in the training and the Fibre Channel infrastructure. All the features are built in with iSCSI. I don't have to say, 'What do I need for remote site replication, or for thin provisioning or SmartClone technology to reduce the amount of VM images I have to manage?' You don't have to buy anything extra; it's all built in."

Users find iSCSI good enough

As price becomes more of an issue, companies are more likely to take a look at iSCSI. Even if it can't outperform FC, customers find it's often good enough at a significantly lower cost.

CIO Ben Weinberger said he replaced a "big bad expensive Fibre Channel box" with two Dell EqualLogic PS6500 systems after he arrived at Kansas City-based law firm Lathrop & Gage LLP in 2008.

"It's a fraction of the cost [of Fibre Channel] and does plenty for us," he said. "Performance is fine for what we're doing. We're not processing a zillion transactions per second. A Fibre Channel SAN will outperform an iSCSI SAN, but an EqualLogic iSCSI SAN meets our needs without a problem. We manage around 20 TB of active data with it, and we tax the system. I don't need a Ferrari when a Camry will get me where I need to go."

Shawn Houston, technical lead in the Biotechnology Computing Research Group at the University of Alaska Fairbanks, said he's been running an iSCSI storage system with Nexsan Technologies storage and a Sanrad Inc. SCSI-to-iSCSI bridge for almost four years.

"We would have preferred to have gone to a [Fibre Channel] SAN, but price considerations drove us toward more of a commodity solution," he said.

Houston said he's happy with his decision. "When I benchmark the system, I see about 80% of the performance of Fibre at a fraction of the cost," he said. "I've never been disappointed with it."

10 GbE, FCoE loom on horizon

For most of its life, iSCSI chugged along at Gigabit Ethernet speeds while Fibre Channel moved up the chain from 1 Gbps to 2 Gbps to 4 Gbps and now 8 Gbps. But the availability of 10 GbE gives iSCSI a performance jolt. HP's LeftHand Networks has supported 10 GbE for approximately a year, and Dell recently added 10 GbE capability to EqualLogic systems. Most in the industry predict slow adoption rates for 10 GbE iSCSI, however.

FCoE also bears watching. FCoE allows organizations to run FC and Ethernet on the same network. While there's speculation that FCoE will prompt organizations to bypass iSCSI, the consensus is that smaller organizations will stick with iSCSI while enterprises with a heavy investment in Fibre Channel will go with Fibre Channel over Ethernet. In any case, FCoE is still a few years away from mainstream adoption, according to most experts.

IDC's Yezhkova said she doesn't expect a sudden rush for iSCSI with 10 GbE, but a gradual replacement of Gigabit Ethernet with 10 GbE. She also said FCoE will likely slow iSCSI adoption a bit but not stop it. "We expect iSCSI will continue to eat into the Fibre Channel space," she said.

Forrester Research's Reichman said iSCSI is "less disruptive than FCoE, which requires all 10 Gig and all lossless Ethernet. That's an advantage in iSCSI's corner. It can be deployed more gradually and deployed with what you have now and you can beef it up later."

This was first published in February 2010

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