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USA.NET eliminates LUN problem with scale-out NAS

Dave Raffo, Senior News Director

Seccas, the archival service division of USA.NET, an email hosting company, turned to Isilon Systems' scale-out NAS

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to solve its LUN management problem by eliminating LUNs.

Isilon storage has no LUNs, which helped Seccas solve a tactical headache with its EMC CX300 SAN. The company had to archive millions of small files for its message archiving services, but it is a Windows NTFS environment, and that meant there was always a chance the system would do consistency checks on the files residing on LUNs. Those checks could take days, and data residing on the LUN would be offline until the checks completed.

"Our problem was we were dealing with millions and millions of tiny files. So that created a practical issue for us," said Justin Greene, vice president of archival systems at Seccas/USA.NET. "We needed large LUNs but we could not create large LUNs because of the risk of running into a consistency check. We would have to take down that LUN and any data on that LUN was inaccessible."

Another problem for Seccas was that whenever a client's data file grew to a certain size, it had to be moved to another NAS head. Greene said his staff was constantly moving client files to optimize space.

"It could take three days to move a client between LUNs," he said. "It was a lot of administrative overhead and it really doesn't scale well."

Seccas kept its Clariion for database storage, but moved its files to Isilon storage in 2008 and has since expanded significantly without experiencing NAS sprawl -- Greene said he has been able to scale without problem.

Isilon's OneFS operating system requires no LUNs. It runs systems as one file system, namespace and volume, no matter how many nodes -- or how much storage capacity -- is added. Isilon customers usually start with a minimum of a three-node cluster that can scale up to 144 single nodes written within a single cluster.

"They have eliminated LUNs entirely from their architecture, which is unique in the storage market," Greene said. "Most NAS systems still have LUNs created on the storage device."

Greene started out with six Isilon IQ 6000i nodes at 36 TB of raw capacity and has since grown to eight 12000X nodes with 12 TB of capacity each as well as eight 12000ex expansion nodes at 12 TB capacity each and two 36000X nodes with 36 TB capacity each. Along with files, the company stores virtual servers on the Isilon storage.

"Whether you add a different version of hardware, different nodes or different density levels, it never creates another LUN or volume or management for another file system," said Sam Grocott, vice president of marketing at Isilon Systems. "The benefit that [Greene] gets is he can add different storage systems in less than 60 seconds and his performance and capacity scales linearly as he adds more nodes or appliances. That is done from one volume and one file system. Your single pool of storage gets bigger with no management overhead."