New Approaches to the VDI/Storage Dilemma

Arthur Cole
Slide Show

When Is It Right for a Business to Consider Desktop Virtualization?

Tips for determining whether desktop virtualization is right for your business.

It seems that Virtual Desktop Infrastructure (VDI) is following the same trajectory as previous technology innovations: A rush of enthusiasm followed by rapid deployment that leads to the inevitable letdown as reality sets in.

In the case of VDI, the reality is the impact the technology has on existing storage infrastructure. For many organizations, the need to shore up legacy systems has been a major factor in the relatively lukewarm embrace of VDI despite its vast potential to cut costs and streamline data operations.

Lately, however, proposed fixes to this problem have been coming at a steady clip. The solutions range from improved caching and management capabilities to higher-speed storage options.

Atlantis Computing, for example, recently upgraded the ILIO platform to smooth out some of the rough edges when integrating VMware View and other systems into existing infrastructure. The system, which can be deployed on a virtual appliance, provides image consolidation, I/O offload and other management functions designed to streamline VDI's presence on network and storage resources even as it maintains responsiveness and reliability for end users.

For SAN users, VDI presents a particular challenge as floods of new desktop images can quickly overload available storage controllers-even more so than a virtualized server environment. What's needed, according to tech blogger Brian Madden, is a local virtual storage option to streamline access to storage through a VDI host server. Madden is convinced that DataCore's new SANmelody software fits the bill by housing the storage virtualization system on the same hardware that hosts the virtual desktop. While this does add an extra burden to local memory, CPU and other resources, it turns out performance is actually enhanced by the elimination of external traffic and the block-cache and I/O latency it engenders.

Some firms, however, are offering a more direct approach. Xiotech recently launched a new line of hybrid storage drives that the company says boosts I/O to a level that can easily support even the most challenging VDI environments. The Hybrid ISE device uses what the company calls Continuous Adaptive Data Placement that delivers 60,000 IOPS in a single 3U unit-scaling up to 900,000 IOPs per rack. The company says the drive is drawing interest across a range of applications other than VDI, including data warehousing and high-volume cloud computing.

Improvements to storage are necessary for VDI, according to Xangati VP David Messina, but you also need to take a good, hard look at wide area networking. The fact is, the vast majority of VDI pilot programs fail only after users start accessing desktops over the WAN, VPN or other low-speed link. Fortunately, there are many ways in which VDI platforms can be tweaked to accommodate existing network capabilities, such as altering protocol parameters to adjust features like screen resolution, audio and USB redirection. You'll also have to implement a wide area management and monitoring system to guard against sudden traffic spikes that can hamper VDI performance.

Despite these improvements, the jury is still out on VDI. Although the number of seats is growing, it still makes up only a tiny fraction of the worldwide desktop universe. There is little doubt, however, that the vendor community sees gold in the technology and will continue to chip away at the objections one by one.

The idea is to reach a critical mass of users and then let the fear of being left out of the next big IT revolution take control.

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Add Comment      Leave a comment on this blog post
Feb 11, 2011 4:19 PM Alex Miroshnichenko Alex Miroshnichenko  says:

The fact that storage cost is the main obstacle to widespread adoption of VDI is hardly news at this point. No surprise that the existing vendors are trying to adopt whatever tools they have at their disposal to the emerging needs: if you have a hammer you tend to treat every problem as a nail.

The core issue here is that VDI takes the I/O performance problem of virtualized servers to the extreme.  Systems running large numbers of VDI VMs are the ultimate I/O blender and generate a highly random, small block, write-dominated I/O stream-exactly the worst case performance scenario for most modern storage subsystems

Virsto Software, www.virsto.com, take a unique Server-side Storage Virtualization approach that solves the I/O performance problem. By adding a storage software layer in the hypervisor, designed to handle the specific workload patterns of similar VM's in high density configurations (ie VDI), the I/O bottleneck is unplugged and storage provisioning gets reduced by 75-90%. The economics of VDI suddenly become compelling. With the Windows 7 desktop refresh gaining traction and now a compelling ROI story with storage costs reduced, this just might be the year VDI gets real traction.

Feb 11, 2011 7:24 PM SpeakVirtual SpeakVirtual  says:

I agree that the jury is still out on VDI.  I think many companies doing these massive VDI rollouts have yet to realize the value of the hosted shared desktop model.  And the number 1 thing people are still overlooking is the amount of I/O VDI is going to generate on their storage infrastructure. 

In the end, I think VDI will be a niche' sector of future virtual desktop rollouts, with the hosted shared desktop model being in the majority.  I'm excited about the potential VDI has, but only if it's in it's proper place.

Feb 14, 2011 5:55 PM mycluster mycluster  says: in response to Alex Miroshnichenko

How about using cluster file systems such as ibrix or gpfs for vdi storage systems? The cluster file system based on infiniband is commonly used for high performance computing fields and it was developed for low latency and high throughput.

Common hypervisors support infiniband nic and cluster file servers shows scalability, I think.

Mar 17, 2011 4:15 PM Adam Adam  says:

Another option for solving issues with VDI performance over the WAN is Ericom Blaze, a software-based RDP acceleration and compression solution.  Besides delivering higher frame rates and reducing screen freezes and choppiness, Ericom Blaze accelerates RDP performance by up to 25 times, while significantly reducing network bandwidth consumption over low-bandwidth/high latency connections.

You can read more about Blaze and download a free evaluation at:




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