Many companies that install virtual desktops find their legacy storage environment to be inadequate and too expensive....
Fortunately, low-cost, efficient storage options for virtual desktop environments are available from new, innovative companies.
Here, two IT pros explain how they started out with big name storage and moved to lesser known, but more appropriate, storage products from Nutanix Inc. and Nexenta Systems. A third IT pro supplemented an existing storage system with Avere Inc. systems to boost virtual desktop performance cheaply.
Law firm chooses Nutanix for XenApp
Orrick, Herrington & Sutcliffe LLP put a new company's storage system to the test this year in a Citrix XenApp environment that served up to 1,000 concurrent users.
The international law firms' IT department supports 2,700 employees in 23 offices worldwide, with a global operations center in Wheeling, W. Va. It offers virtual desktops using Citrix Systems' XenApp, backed by VMware's ESX 4.1.
When record snow hit the East Coast of the U.S. in 2009, the company learned just how undersized its Citrix environment really was, said Jeremy Wood, systems engineer for the firm. More users logged in from home than usual. "They just destroyed our Citrix servers," Wood said.
At the time, the firm was licensed for up to 325 concurrent users.
The initial redesign of the environment included a full tray of 15 disks on the firm's EMC Clariion disk array to achieve the performance necessary for 600 concurrent users. The Citrix team requested about 2,500 IOPS. But while all of the disks were needed to provide the right performance, 75% of the 4.5-terabyte (TB) capacity of the tray was wasted in this model, Wood said.
When company management requested support for 1,000 concurrent users, IT began to discuss making a change to its storage strategy, Wood said.
Nutanix launched in August 2011 with a product dubbed the Nutanix Compute Cluster. It combines blade servers, virtual machines and disk into a single 2U unit. The idea is to eliminate latency between the server and storage layers of the infrastructure by combining compute and storage capacity in the same box.
Compared to the cost of a SAN and a Fibre Channel or 10 Gigabit Ethernet (10 GbE) iSCSI network connection, plus separate server hardware and VMware licenses, it's a good deal, Wood said. The Nutanix array also saves on setup time, eliminates cabling issues and cuts down the number of separate interfaces needed to manage the server, networking and storage components. And because of the automated storage tiering, hard disk space is no longer wasted in an effort to boost performance.
Orrick put a demo box from Nutanix through its paces over the last six months, and purchased a production unit which is being set up this month, Wood said. A second unit will be purchased in the first quarter of 2012.
"In one little 2U block, I'm going to have four blades and between 14 and 16 [usable] terabytes," Wood said. "In the future, we're going to buy those boxes when we need to stand up a cluster, instead of buying three or four Dells and back-ending it to a SAN connection."
EMC also offers automated tiered storage using Flash, but Wood said he prefers the simplicity of the Nutanix approach, which handles automated tiering without requiring separate hardware and software licensing.
Medical center moves to Nexenta open source storage
Delano Regional Medical Center (DRMC), a teaching hospital in Delano, Calif., moved to virtual desktops during a transformation from paper to paperless systems a few years ago. Since it uses VMware ESX 4.1 on servers, VMware View 4.6 with PCoIP was a natural choice.
The medical center delivers non-personalized virtual desktops, which require less storage than personalized desktops, so IT tried using the existing Dell/EMC CX500 and NetApp Inc. 2050 storage appliances. The IT team quickly found out that its old way of designing storage systems was inadequate for virtual desktops. Specifically, NetApp IOPS limitations hurt virtual desktop performance.
"We spiked CPU doing deduplication on our desktops and end users complained when using VDI desktops," said Keith Brennan, a network specialist at DRMC.
Brennan searched for a better, lower cost storage option and found an open storage product from Nexenta Systems. He gave the NexentaStor 3.0.5 system a shot and when performance increased, he replaced the EMC CX500 and NetApp 2050 appliances with it. Now, he runs the Nexenta product on two commodity SuperMicro servers running as dual heads attached to a SAN.
With Dell, EMC and other big name storage vendors Brennan considered, he said the lowest SKU for a 10-20 TB storage cost about $100,000. Of course, pricing varies depending on the type of system and Dell Equalogic systems are available for much less than that, based on one Equalogic SAN pricing list.
But with Nexenta, the flexibility to use commodity hardware also lowers the cost by 40-50%. He uses a hybrid storage pool with solid state and said that latency is a millisecond.
"The key here is the open architecture -- you can throw whatever you want at it," Brennan said. "Our price to performance ratio is low, which makes it an asset for VDI project."
Nexenta also recently launched a "Nexenta VDI" bundle that simplifies the process of installing VMware View 5, reducing the number of steps involved from 150 down to just three. The bundle integrates Nexenta storage, View and ESX. NexentaVDI with View 5 will be generally available in Q1 2012. Pricing has not been disclosed.
The company said it plans to eventually offer a similar product for Citrix XenDesktop and Quest Software.
School district gets View performance fix with Avere
Instead of replacing an aging storage system to reduce virtual desktop boot times, the Belchertown, Mass. School District decided to speed things up by adding appliances from Avere, Inc.
The district, which has 400 employees and 2,600 students in five schools and one central office, has about 1,000 PCs, 500 of which are virtualized using VMware View 4.6. The virtual desktop infrastructure rides on three Cisco UCS servers that run ESX 4.1. These were attached to two NetApp FAS2020 iSCSI SANs when director of technology Scott Karen was hired this past summer.
At that time, the FAS2020 (which has been discontinued) was overmatched by the demand that came from boot storms at the beginning of classes each day. Some machines were taking up to 10 to 14 minutes to boot. "It was either run through another semester with teachers with pitchforks outside my office door or come up with a solution quick," Karen said.
With limited time and budget, replacing the FAS2020 wasn't feasible. Instead, two Avere FXT 2500 systems were brought in to front the array, boosting its performance without requiring a full refresh.
Each FXT 2500 contains 72 GB of DRAM, 2 GB of NVRAM memory and 3.6 TB of SAS disks. Data is automatically moved between these tiers and the NetApp array on the back end, with the Avere devices acting like a giant cache in front of the NetApp.
As a result, the longest a machine takes to boot now is between three and four minutes, and most take two to three, Karen said, estimating that the Avere systems came at about half the cost of a new NetApp array.
"If I had the money and time, I would've gone with a new FAS 3750 with 200 gigabytes of NVRAM built into it, but … to install that and get all the datastores moved would've been three to six months worth of work" in addition to being more expensive, Karen said. "[Avere was] able to come in quick and get done within 30 days [of] the time I decided we needed to move."