Tired of throwing hardware at latency problems hindering its virtual desktop infrastructure performance, the IT team at Northern Arizona University found a software cure.
The Northern Arizona University (NAU) campus in Flagstaff, Ariz., is home to 20,000 students who were increasingly seeing serious performance lags when using applications in the 13 TB XenDesktop environment. The IT team found Nexenta storage software at the Citrix Synergy conference in May 2014, and decided it was a good fit for NAU.
"A real main issue arose with interactive sessions both in terms of login times and direct user experience. There were times you'd hit a key and there would be a perceptible delay," said Tobias Kreidl, academic team lead for the university's IT department.
NAU had been adding more storage and servers to their environment to deal with performance, which was too costly to continue. "We were looking for something that above all would get us away from the linear model of storage where if you need three times as much you buy three times as much," Kreidl said.
On the hunt to transform the existing data center
Nexenta's NexentaStor is software-defined storage that runs on commodity hardware for file or block storage. Kreidl said that when he and senior software systems engineer Duane Booher attended the Synergy conference they wanted something that could run on their Dell infrastructure. That was one of the first things that drew them to Nexenta, which has a partnership with Dell.
They were also on the lookout for storage that provided thin provisioning, which was lacking in their previous iSCSI environment. NexentaStor's use of NFS was something that provided this, so in order to be sure switching to NFS could provide the performance they needed, they set NexentaStor up in a test environment for several months before making the purchase.
Thin provisioning, caching provide noticeable improvement
The ability to thin provision turned out to be a big win for NAU. That, along with inline compression that the Nexenta storage provided, was able to shrink the 13 TB of data to 800 GB.
In addition, caching was integral to solving the performance problem -- NAU now sees a 93% cache read rate in their virtual desktop infrastructure (VDI) environment. "The vast majority of reads are coming right out of the memory of the NexentaStor server, so they don't have to dig back to disk every single time in order to retrieve things, hence a great improvement in overall response times," Booher said.
"We could immediately [see an improvement in] certain types of things such as scrolling through an Excel spreadsheet, for example. Before you would see definite latency, even sometimes hopping from cell to cell, and that completely disappeared," Kreidl added.
He said that with the unused capacity from NexentaStor, NAU now has the flexibility to expand its VDI environment, in addition to adding new applications. He said the next major feature he plans to roll out is high availability for backup and live maintenance.
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