Virtual Desktop Infrastructure, or VDI, allows IT administrators to centralize and simplify the provisioning and administration of user desktops. Estimating the I/O performance needed across hundreds or thousands of consolidated desktops is a considerable challenge. Average I/O utilization is not a good metric because it does not account for I/O spikes such as “boot storms&rquo; and “login storms&rquo; that slow performance and frustrate end-users. Allocating too much I/O per user increases hardware costs, while allocating too little I/O per user reduces productivity and degrades performance.
In addition, persistent virtual desktops often consume 40—80GB per desktop in storage capacity, which limits the number of desktops each server or storage system can host. This increases the cost per desktop and the amount of infrastructure required for VDI deployments.
Because VDI performance is so difficult to reliably simulate, many organizations don’t know whether their storage system will handle their data transactions until the VDI deployment is in production. Many storage array vendors address this issue with claims that they can scale performance with added controllers and disk shelves. However, scaling traditional SAN or NAS storage is far from linear, making it impossible for them to guarantee a specific number of supported users or performance level at a given cost. Centralized storage also has high up-front costs that are often cost-prohibitive for smaller scale deployments.
Together, Fusion-io and Atlantis Computing™ deliver a best-in-class storage solution for persistent virtual desktop deployments. Fusion Powered VDI servers deliver uncompromised I/O to support a guaranteed number of users at a far lower cost than centralized storage. Atlantis ILIO storage optimization software works with ioMemory products to reduce the storage capacity required per desktop by up to 95 percent, enabling ioMemory to host up to 20 times more desktops. By increasing the number of desktops per ioMemory product, customers dramatically reduce the cost per desktop. Performance and cost scale linearly with each VDI server added, whether you are supporting 100 or 10,000 users. HA is handled by having a standby server available and user profile data housed on network storage. In the unlikely event a server fails, users are simply provided a new desktop on the standby server. When they login, all of their documents, configurations and settings will be available instantly. Due to the speed of ioMemory, booting up a new desktop takes a fraction of the time it otherwise would have.
Atlantis ILIO Center fully automates the deployment and configuration of Atlantis ILIO virtual machines on each server across multiple racks, providing NFS data stores that are ready to be used for provisioning by the VDI solution. The virtual desktop images are provisioned on a highly optimized Atlantis ILIO datastore that uses only a small amount of Fusion’s ioMemory capacity. User profiles, including user files, settings, and data are streamed to the desktop over the network from a file share or network-based storage system.
Figure 1: ioMemory and Atliantis ILIO in VDI deployment structure.
The joint Fusion-io and Atlantis ILIO solution supports both VMware View and Citrix XenDesktop.
Hawai‘i Medical Service Association (HMSA), the Blue Cross and Blue Shield of Hawaii, has more than 600,000 members, $2 billion in revenue, and 1,700 employees.
The cost and operational complexity of maintaining and refreshing thousands of physical PCs drove HMSA to rethink its desktop computing strategy and initiate a switch to virtual desktops. After a costly desktop refresh in 2009, HMSA was reluctant to replace its entire fleet of more than 2,000 physical PCs at a cost of $1.8—1.9 million ($1,397 per PC).
HMSA found that the I/O profile for a virtualized Windows desktop was very write-intensive, required a large number of low latency IOPS to perform well, and suffered from a phenomenon known as the I/O blender effect, which makes it difficult for storage systems to keep pace. With traditional shared storage, HMSA simply wasn’t able to deliver equal performance to a physical PC. After researching the options, HMSA selected Atlantis ILIO storage optimization software in combination with flash memory-based ioMemory from Fusion-io to deliver the best combination of performance and cost.
While performance was the primary driver, it was also critical that HMSA be able to maximize the number of users that could be run on a single server equipped with an ioDrive to make the project economically viable. With a 40GB image, HMSA was only able to fit 30 virtual desktops per 1.2TB ioDrive card. Atlantis ILIO reduced the size of the virtual desktop images by 90% to 4GB, enabling HMSA to reach a density of 200 virtual desktops per server with 30% of the drive still available for growth.
Using Atlantis ILIO and Fusion-io, HMSA was able to achieve 10 times the IOPS of a normal PC hard drive and deliver performance similar to a laptop with its own SSD drive. HMSA virtual desktops have a boot time of 7 seconds and launch applications such as Microsoft Word, PowerPoint,and Excel in less than 1 second. With Atlantis ILIO Storage optimization software, HMSA cut infrastructure costs by 59%, saving $1,150,900.
Figure 2: Total CAPEX cost and performance per persistent virtual desktop (four scenarios).
With Fusion-io and Atlantis ILIO, customers can now safely and inexpensively transition to a persistent virtual desktop environment, while eliminating I/O storms, maximizing performance, and minimizing infrastructure and operating expenses.
For more information, please email us at sales@atlantiscomputing.com or visit www.fusionio.com.

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