While VDI continues to catch on, storage and I/O challenges still seem to be one of those roadblocks holding people back.  But it doesn't have to be.  VDI solutions have come a long way, and so have storage options.  I recently spoke with Chad Marlow, IT Director for Enumclaw Public School District in Washington state, and asked about their recent VDI deployment.  Chad talked about the challenges he faced in deploying VDI in his school district – which he's now successfully running, with plans to expand in the near future.

VMblog:  What led you to initially choose to deploy a virtual desktop infrastructure (VDI)?

Chad Marlow:  Honestly, it was a multitude of reasons. Probably the most important driver was our requirement to provide online state testing for reading. It was a first for our district and we were concerned with reliability, consistency of experience, and ease of software updates. Without a formal software management solution our environment is more similar to an unmanaged desktop landscape. Therefore I needed to either quickly bring in a fully baked and operational desktop/software management solution or find a creative, innovative way to solve these challenges.

Secondary drivers included ease of desktop management for tech staff, consistent user experience over the life of an endpoint client, and a sustainable deployment both financially as well as with limited support staff. From a school perspective, it will cost less because they are not purchasing thick clients (desktops) with finite replacement cycles. We deploy and spec zero clients with a life expectancy of 8-10 years. As desktops age out we attempt to repurpose them as thin clients until we can afford to replace them with a zero client. Furthermore as software upgrades, the user experience, including performance, remains consistent (i.e., performance will not suffer as the device ages).

VMblog:  What were the major challenges you initially worried about in successfully deploying VDI?

Marlow:  The biggest challenge that worried me was our legacy SAN solution. My tech staff were quite thorough in researching currently deployed VDI in various sectors (including business and education) and discovered a consistent VDI failure mode was lack of I/O performance from the storage solution. We discovered that without properly aligning SAN performance to VDI requirements user experience suffers and results in failed or frustrating VDI deployments. We realized early on that our legacy SAN was woefully inadequate to support the VDI deployment we were planning. The timing was very good as our current SAN was approaching 4 years old and was in need of replacement.

Another challenge was to deploy two brand new concepts in our environment in a period of about four months: state required online testing and VDI. My requirement was to have students utilize VDI for state testing exclusively. For our district this was very high stakes - our students had never used either a VDI environment nor had any experience in online testing. If either one were to fail or not deliver my expectations it would result in low student performance scores for a particular school due to technology. This was absolutely unacceptable.

A third constraint for this project was that all the students would be utilizing newly purchased wireless laptops for this VDI/online test experience. This places an additional burden on our wireless network and we needed to be aware of both latency and packet loss requirements for both VDI as well as the state testing software. Our wireless network had previously been designed only for a "distribution" network and not a "density" network. Wireless network problems could affect either VDI or test software or both. The result would again be low student scores due to technology.

Those were the major challenges I faced in deploying VDI technology in a short time (four months) with high stakes and a "must work the first time" directive.

This will allow each and every student to access the test in the same way as well as allows us to maintain a specific software version across hundreds of desktops with little to no effort.

VMblog:  How did you overcome those challenges?

Marlow:  We took each area a step at a time. For our storage solution we provided a Request for Information (RFI) document to several storage vendors which provided our performance requirements, modes of operation, VM troubleshooting, and as much information about our environment as possible. We started from a list of ten storage vendors, narrowed it down to three and ultimately did a "bake off" between the finalists. We settled on the Tintri T540 for its high-performance hybrid architecture, deduplication and compression technology, individual VM visibility, and excellent support structure. This solved the problem of storage performance.

We overcame the introduction of two new technologies simply by performing significant testing. This took the form of load testing, student/teacher professional development, classroom testing, and hardware tests. Each grade of students was required to take the "practice test" a minimum of four times prior to the "real" test.

To overcome the wireless challenge we developed a list of specific classrooms where the "real" test was taking place and augmented the locations with additional access points. The four practice tests for each grade were required to take place in the actual rooms so we could get an idea of wireless performance. It was during this phase of the project we struggled the most. We found the software was very sensitive to wireless band hopping (802.11n to 802.11a, etc.) as well as access point hopping.

In the end, however, we did manage to create a stable environment to allow for a completely successful state test.

VMblog:  How large is your current deployment, and what's its main usage?

Marlow:  Phase 1 "state testing VDI" included spinning up 250 VDI desktops and they were originally for the state testing application. They have shifted now to a general education pool. We also have 30 VDI dedicated to another type of testing (non-state test) as well as a few lab pools.

VMblog:  Do you have plans to further expand your VDI deployment?

Marlow:  Absolutely! Phase 2 (in progress) includes adding 300 VDI to be completed in 3Q2013. Phase 4 will be to add another 250 VDI to support an additional subject area of testing by 2Q2014 and the final stage will be to determine how many desktop we need for 100% online testing in 2Q2015. My overall goal is to approach 80% VDI environment by 2015. We will most likely be in the market for a second storage solution by that time both for performance and expansion.

Fortunately, we evaluated Tintri also from an expansion lens and they would be an excellent choice to expand our storage hardware!

VMblog:  What type of advice would you give to your IT peers that are currently considering VDI?

Marlow:  Understand what goals you are trying to accomplish and determine if VDI will be the best solution for you. Once you've decided to go down the VDI path, determine your infrastructure needs through some sort of gap analysis and use the results to perform modifications to your environment. Talk to similar organizations that have already gone down this path and learn from their experiences. Don't be afraid to try new things!

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Thanks again to Chad Marlow, IT Director for Enumclaw Public School District in Washington state, for taking time out to speak with VMblog.