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At the end of 2014, C&S, based in Syracuse, New York, switched its on-premises storage from aging EqualLogic PS6500 and PS5500 arrays to a NexGen Storage N5-300 Hybrid Flash Array. NexGen arrays use PCIe cards along with hard disk drives.
NexGen was still part of SanDisk when C&S implemented the N5-300, but the hybrid array vendor spun out on its own in January. The N5 NexGen arrays were originally developed to use quality of service (QoS) for storage management before the startup was acquired in 2013 by Fusion-io, which was subsequently acquired by SanDisk in 2014.
C&S senior network administrator Jeffrey McGowan said he was impressed with the well-traveled technology in his N5, both the use of PCIe flash instead of solid-state drives (SSDs) and its QoS.
"We felt the PCIe flash was a differentiator," he said. "They're not using a technology that everybody else is using. We think PCIe is the way a lot of disk controllers should go."
McGowan said instead of using a separate SAN for virtual desktop infrastructure (VDI), he stores his virtual desktops on the same 3U NexGen array that he uses for primary storage. That includes payroll and accounting applications as well as Microsoft Exchange, SQL Server, SharePoint, Active Directory and CAD licensing servers.
The firm, which provides engineering, architecture and construction services, also upgraded from Gigabit Ethernet (GbE) to 10-GbE iSCSI when it switched storage. He said since switching over, average write latency has decreased from 12.9 milliseconds to 3 milliseconds, the average disk queue depth dropped from 5.8 to .23, and the time it takes to provision a VDI workstation went from around 90 minutes to around 20 minutes.
McGowan said he likes NexGen's dual active-active controller architecture, and the QoS comes in handy for VDI. NexGen's QoS lets customers create policies to guarantee high-priority applications receive the highest performance.
"We built QoS policies based on our core apps," he said. "Exchange and virtual desktops are policy one. Login data from Exchange and our payroll application are policy two. The bulk email system that we do a lot of searching on is policy three. Lower-end archive data and OS data goes into policies four and five.
"Policy one data sits in flash. If somebody goes to do a read in VDI or Exchange, it's in flash. The read is instantaneous."
C&S had no flash on its EqualLogic arrays, and McGowan said he looked for a hybrid array for a replacement as those systems came close to end of life. He considered newer EqualLogic models and also looked at systems from Nimble Storage and Tegile Systems.
"We knew we couldn't afford all-flash, but we could get into the hybrid arena," he said.
McGowan said he also liked Nimble's architecture but felt too much of its capacity claims were based on compression, and he couldn't be sure what the actual compression rates would be until he bought a system.
"The thing we didn't like about Nimble was the idea that everything is compressed and the space you were buying was less than you think you needed, and you based your assumptions on compression," he said. "I had a really uneasy feeling about that. The theory behind it is good, but we don't want those [performance] penalties for data reduction."
He said the N5-300 gives him 40 TB of available space -- compared to 89 TB of usable capacity on his EqualLogic systems -- but C&S currently uses only 15.6 TB.
Rather than using compression and data deduplication, C&S keeps its storage array capacity requirements down by moving file data to Amazon Simple Storage Service with Panzura cloud controllers in its remote offices. C&S uses the cloud for data that users share, such as CAD files. McGowan said the firm has about 15 TB of file storage in the cloud.
"We split our file services off in 2013," he said. "Anything we collaborate on is in Amazon. We have a caching controller [Panzura] in each office, and collaboration between offices is seamless."
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