Improve VDI Performance by Increasing IO

Posted by Tom Rose on Oct 1, 2014

This blog is an excerpt from the Unidesk eBook Ten Quick Tips for Scaling VMware Horizon View.

Many enterprises are finding that moving Virtual Desktop Infrastructure (VDI) from pilot to production is harder than they thought. A VDI pilot that had great performance for 50 users is now not performing well for 100, 250, 1000 users and beyond.

Fortunately, new technologies, tools, and techniques have emerged to make scaling VDI much easier. In this series of blog posts gives you will learn 10 tips for achieving successful, full-scale VDI deployments based on real-life case studies, so you can benefit from what your peers have already learned.

The Problem: Insufficient storage IOPS

Insufficient storage IOPS (input/output operations per second) is one of the biggest barriers to VDI scale. Typical desktop use is write-heavy (often 80/20), but boot storms and anti-virus scans introduce read spikes. Overnight maintenance tasks such as desktop rebuilds to apply Windows patches and application updates create additional heavy write bursts. Ensuring you have enough IOs per Second (IOPS) to deliver desktop performance that's acceptable to end users while accounting for these spikes is critical to VMware Horizon View success.

Why is it a problem?

This issue rarely surfaces during pilots because there aren't enough desktops running to stress your existing SAN array. But once you start hitting those old rotating disks with many server-hosted desktops at the same time, the IO capabilities of mechanical storage will be quickly exceeded. And your users will start asking for their old PCs back. 

The Solution: Increase IO

New storage solutions that leverage the falling price of solid state drives (SSD) and flash memory has given IT organizations new ways to cost-effectively meet the performance requirements of demanding virtual desktop workloads:

  • Flash optimized hybrid storage. A new generation of hybrid SAN arrays from vendors such as Fusion-io, Nimble, Tegile, and Tintri use high performance RAM and/or SSD in combination with traditional HDD to optimize capacity, performance and cost. Frequently accessed (hot) data is cached in the SSD or RAM tiers and writes are coalesced to maximize performance, while infrequently accessed (cold) data is stored on HDD to maximize capacity.
  • All-flash storage arrays with data reduction technology. A new generation of all-flash arrays from vendors such as Pure Storage offer inline data reduction techniques including deduplication, compression, and thin provisioning to dramatically reduce the data footprint. The result is a logical array size that is 5-10X larger than its actual raw capacity, driving down cost per GB and making all-flash storage affordable.
  • Software-defined storage. A new generation of converged server and storage systems from vendors such as Nutanix enable lower-cost local storage to be managed as part of a virtual storage pool shared by many hosts. This enables enterprises to fully leverage server-attached flash technology, and avoid the end-to-end latency incurred when flash is simply added to centralized, network-based storage systems. VMware's Virtual SAN solution takes a similar approach with technology targeted-for now- at smaller VDI deployments.

Customer Examples

These customers experienced the storage challenge in their first attempts at virtualizing desktops. Both are now successfully scaling their VMware Horizon View deployments, due in large part to the new storage technologies discussed above:

  • Screen_Shot_2014-09-08_at_12.54.25_PM-1Hartnell College in northern California encountered a range of storage-related problems in its first attempts at VDI. The college is now on its way to 2,000 concurrent VMware Horizon View connections with Tegile flash-enabled storage arrays. Learn more about how the college scaled VDI by watching the on-demand webinar "Hartnell College's Keys to VDI Success."
  • Screen_Shot_2014-09-08_at_12.54.11_PMWaxahachie Independent School District in Texas didn't meet faculty, taff or student expectations for performance with its first 900 virtual desktops. An all-flash storage array from Pure Storage helped change the perception of VDI at the K-12 school district. Learn more about how the school scaled VDI and see a live demo of their environment in the on-demand webinar "Texas School District Makes the Grade with 1,500 Desktops."

Continue learning about this topic by reading the next tip: Improve Graphics Performance

Topics: VMware Horizon View

Posted by Tom Rose on Oct 1, 2014

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