He had already provisioned Fibre Channel SAN infrastructure as a special service for contract customers, but Intelenet’s generic offering was all DAS. “We looked at extending Fibre Channel to all our customers,” he explains, “but it would have cost 10 times as much as iSCSI. Then there is the skill-set issue. No member of our 24/7 staff is afraid to get on these [iSCSI] devices. I don’t think this would be true for Fibre Channel.”
Intelenet built its SAN on data arrays from EqualLogic, an iSCSI storage hardware vendor. EqualLogic also ships with virtualization software running on clustered storage.
EqualLogic went head to head with the Clariion CX Series from storage giant EMC in a final, proof-of-concept test at Safeway Insurance Group. Mike Leather, network services manager there, says, “Even after sending out three teams, the EMC folks could not show me the performance stats I needed, so we went with the PS line from EqualLogic.”
Leather needed better performance on his primary business system, a Microsoft SQL Server cluster. The I/O to the system’s DAS was the bottleneck, which immediately suggested a SAN solution. “We looked at Fibre Channel, but iSCSI is so much cheaper,” Leather says, “and you don’t need to buy any HBAs or Fibre Channel switches.”
“We had it up and running by mid-October,” Leather says, “but did not go live until February 2006. We were extra-cautious since our whole business runs off this system.”
Since then he has migrated storage for other systems to the SAN, including secondary SQL databases and Microsoft Exchange. In summer 2006, he started a new project, replication, for which he bought a new PS 3600 and EqualLogic replication software. “We now have two equal architectures, and we are replicating our database every five minutes.”
Right now both of these are at the home site in Westmont, Ill., but in April, Leather says one will move more than 800 miles to a secondary site. “This will be iSCSI over 10Mb metro Ethernet,” he says. “Robust disaster recovery. By the second half of 2007, we plan to have full two-way replication, two fully redundant hot sites. By the end of the year, we plan to have load balancing as well.” In that same time frame, Leather also plans to start testing virtualization.
So far, Leather has had no major problems, but he recommends that before you consider iSCSI, you look carefully at one thing. “If you have not made major improvements to your network infrastructure in the last three years, you had better do it. We were OK since we had put in Gigabit Ethernet with a new switch a few years back.”
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The routing let Brinegar segment his iSCSI traffic from his production network. This is an important consideration as iSCSI’s greatest strength, the fact that it can run over your standard IP lines, can also be a weakness if storage traffic drags down mission-critical systems.
Brinegar uses IPStor software from FalconStor, which transforms a high-end Linux box into a RAID array with four terabytes of storage. “Our main goal was CDP, continuous data protection, and I had a limited budget of about $40,000. iSCSI was really the only option given my performance requirements.”
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