Storage Considerations for Virtual Desktops: Understanding VDI and its impact on storage

Welcome folks! This blog post is first in the series of three posts that will discuss storage challenges related to virtual desktop deployments and explore ways to overcome these challenges. In the first post we will primarily discuss the impact a VDI workload can have on the supporting storage system, and how that affects your VDI project success.

With proliferation on many client devices that vary in form factor, desktop virtualization may be the most relevant technology for streamlining client device management and providing a consistent user experience. By separating operating system and applications from physical client devices, desktop virtualization helps streamline management, lower operational expenses and facilitate adherence to compliance and security requirements.

However, if not correctly designed, desktop virtualization can spell disaster. There are three primary factors that determine the success of your VDI project:

  • User experience that is consistent and acceptable by the end users
  • A positive ROI that justifies this shift in client computing model
  • Simple storage management and scaling

And storage is the critical element in addressing all of these factors. Storage plays a vital role in enabling successful VDI roll-out. Let us take a quick look at what it means for storage to host and service your virtual desktop workloads.

Why storage matters:

First of all, VDI is not just another virtualized workload. VDI workload is highly variable in terms of I/O demand it places on supporting storage infrastructure. Storage that supports a VDI environment essentially stores the virtual machines (VMs) that power the client devices. Every time a client device accesses the OS, application or user data, it generates I/O requests for the storage infrastructure. As you can imagine, this access pattern is not evenly spread-out over the course of the day. There are periods of time when many client devices are accessing large amounts of data from the VDI infrastructure, and the supporting storage arrays. For example, in the morning when a large number of client devices boot simultaneously, they generate massive amounts of concurrent I/O requests for the storage devices. this phenomenon is called boot storms. If the storage is not able to service these requests within acceptable latency, the client devices experience delays and the user experience is compromised.

Overprovisioning of storage can help solve this issue to some extent. By overprovisioning, you allocate more storage capacity, and thereby typically more disk drives, to your VDI than you really need. The ability of storage to handle certain number of Input Output Operations per Second (IOPS) is a function of the number of disk drives it contains. A larger number of disk drives in the storage system can support a higher IOPS demand. However, this is cost-inefficient. That leads us to our second challenge; the cost of your storage system.

It is important to realize that when you implement VDI, you are actually moving the entire client attached storage; all the local hard disk drives (HDD); over to your enterprise datacenter. The storage infrastructure that supports VDI deployments is more costly than the client attached HDDs. When you combine the need for lots of enterprise storage, with the possibility of overprovisioning capacity to meet performance goals, costs can become an issue. Carefully managing your storage footprint is critical in order to achieve the ROI.

Lastly, VDI deployments are typically carried out in phases, starting with a limited and pilot deployment and slowly extending the rest of the organization. As the VDi implementation grows to accommodate more and more users, it is imperative that the storage is able to scale simply and without complicating storage management.

I will discuss throughout this blog series the possible ways you can manage and mitigate these storage challenges.

Take away:

A successful VDI implementation can help streamline desktop management, lower operational expenses, and facilitate security and compliance adherence. However, inadequate design considerations can lead to failure. While designing your VDI environment, it is critical that you ensure acceptable user experience, positive project ROI, and a simplicity in scaling and managing the storage infrastructure. Proper storage selection can help ensure optimal performance, reduce storage footprint and simplify storage management and scaling. Storage is the key enabler in ensuring a successful VDI roll-out.

In the next blog post, I will go over a storage sizing illustration for delivering optimal user experience. Following that, in my third and final post in this series, I will explore key storage features that enable successful VDI implementations. Stay tuned and join the conversation on Twitter, @Dell_Storage.

About the Author: Vikram Belapurkar