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Users leaving Fibre Channel for iSCSI SANs find pros, cons

Beth Pariseau
Whether or not 2007 becomes known as the "Year of iSCSI," more and more users are making the transition between legacy Fibre Channel (FC) systems and iSCSI for production data. Two users, who recently made

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the switch, said they've found performance and reliability on iSCSI storage area networks (SANs) suitable for their purposes. But management and configuration issues have, at times, led to bumps in the road.

Last year the U.S. Army Corps of Engineers branch in Huntington, W. Va., replaced a six-year-old Hewlett-Packard Co. (HP)/Compaq HSG80 Fibre Channel array with an iSCSI SAN from LeftHand Networks Inc. The Army Corps of Engineers had never been happy with the complexities of managing a Fibre Channel SAN, but as IT specialist Mark Kash said, "You make an investment, you don't just throw it away. This is taxpayer money, and we had to suffer until we got some kind of ROI out of it."

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But dealing with the Fibre Channel SAN soon became so miserable that Kash said his staff began provisioning new servers with direct attached disk (DAS) whenever possible, rather than wrestling with networked storage. The Amry Corps of Engineers tried DataCore Software Corp.'s SANSymphony virtualization product to simplify things, but the additional layer of software only added to the confusion. After those experiences, Kash and his team chose LeftHand for its ease of use.

Kash said the SAN's ease of use began with configuration and didn't end there. "The speed is sufficient, I don't have to log in via an obscure console, and any number of people in our department can hook up an Ethernet cable very easily," Kash said. "With Fibre Channel, there's one guy who knows how to do it."

However, there was one instance where the SAN may have been too easy to use. One of the nonstorage administrators in the shop accessed the SAN when trying to help users with a troubleshooting problem, thinking the users were running up against volume size limits.

"They were able to change the size of our volumes, not understanding that what the users were really running up against were quotas we'd set on purpose," Kash said. "That's one disadvantage to ease of use -- people get in there thinking they're trying to help and get a little too brave." Kash said he's since strengthened the password.

Another of LeftHand's claims is that its SAN runs on industry-standard server hardware, rather than requiring the management of complex disk arrays. But Kash said there has been one drawback to that feature -- LeftHand partners with server vendors for underlying hardware. The Army Corps of Engineers' LeftHand clusters started out running on MPC Corp.'s DataFrame 440 server. But as of the release of SAN/iQ 7.0 this year, that particular model from MPC wouldn't support the upgrade, according to Kash.

"LeftHand was really good about helping us get it replaced and eating a big part of the cost," Kash said, but the hardware had to be completely swapped out.

The Gem Group: Price right, MPIO a little trickier

Like the Army Corps of Engineers, promotional products wholesaler The Gem Group had struggled along with an aging Fibre Channel SAN, this time a Magnitude Classic from Xiotech Corp. Initially, the IT folks at the wholesaler were uncomfortable with iSCSI's reliability and whether or not it was "ready for prime time," according to technology manager Brian Smith.

But Fibre Channel expertise was in short supply at Gem Group. "I was the only one in our group that ran that portion of our network," Smith said. "It was more difficult to manage, and there are training issues and costs associated with all of that." When he investigated newer products on the market, including SANs from Compellent Technologies, EqualLogic Corp., LeftHand, Network Appliance Inc. (NetApp), EMC Corp. and Pillar Data Systems Inc., Smith became convinced that iSCSI SANs were indeed ready for prime time.

Smith liked the fact that Compellent and EqualLogic bundled in features such as replication, rather than selling them as separate licenses. "Xiotech and EMC were going to charge us somewhere in the range of $50,000 to $75,000 more for the total package than it was going to cost for Compellent or EqualLogic because we wanted replication," he said.

After that, Smith still wasn't done pushing the vendors on price. "Probably the biggest sticking point during our final evaluation was the ability to extend the service for three years," he said. "EqualLogic gave us terms, but they weren't as attractive." Smith declined to give specifics on the pricing of the different service options.

The Gem Group went with a Compellent Storage Center SAN. Smith finds the SAN's range of reporting capabilities make it easy to use, and, he notes, "I haven't even looked into everything I can use yet." However, Gem Group was still concerned about maintaining the reliability of the system and decided to put in a multipath I/O (MPIO) infrastructure connecting servers to the SAN via a QLogic iSCSI host bus adapter (HBA) and Ethernet switch.

"Getting multipathing right took a little while," Smith said. "You can't just plug everything in and then test it. We had to get a procedure in place for setting up each element in the correct order." Compellent's test and development lab had to get involved, and it took several weeks to accomplish, but it did eventually work.

Now that it's working, Gem Group "has the formula," and Smith said he's happy with the support he received from Compellent during the whole process. "They stuck with me," he said. "They wanted to see it happen too."

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