One of the most frequently overlooked side effects of implementing virtual desktop software is the burden that it will place on the data protection
In a non-VDI world, the most common strategy for protecting endpoint devices is to tell users to "copy the important stuff to the file server," an instruction that is frequently ignored. With VDI, all this user data becomes the responsibility of corporate IT. It's within reach of the standard data protection procedures, but VDI backup could cause a capacity spike on the SAN, depending on what gets virtualized.
There are typically two groups of workers whose desktops are virtualized: the shift worker and the knowledge worker. In the shift worker use case, several workers will use the exact same desktop hardware at different points during the day, but each can have their own "customized" desktop. The hardware they access the desktop through acts like a terminal into the VDI host. In the increasingly popular knowledge worker scenario, on the other hand, all laptops and desktops are encapsulated by creating a local virtual machine on the user's computer to be the "corporate authorized" instance. This instance is then synchronized with an image of itself on the corporate VDI. In both cases, especially the knowledge worker scenario, VDI backup can have a dramatic impact on capacity and as a result have a big impact on data protection procedures.
In fairness, this is not the capacity equivalent of moving the data from hundreds of corporate desktops to the SAN overnight. Storage and virtualization capabilities, such as writable snapshots, compression and deduplication, will all help reduce capacity requirements. There will, however, be a net increase in storage needed to support the environment because users will install their own applications, keep a copy of their own email PST files and, of course, have unique files within their home directories. While individually none of these has a big impact, when combined and multiplied across hundreds or thousands of laptops and desktops, the effect can be staggering. Customers are going to need help in understanding how to protect them.
As long as the space increase is accounted for as part of the backup process, this is a simple capacity management issue. But make sure that it is in fact accounted for. We have seen cases where the VDI project is nearing completion and the backup environment is running out of capacity. As a reseller, you don't want to assume that the capacity increase was addressed by someone else.
Once the space increase is planned for, the next step is for you to recommend how to actually back up those virtual machines. Your recommendation will depend on whether the organization protects laptops and desktops today and how it has deployed desktop virtualization. If the customer doesn't protect desktops and laptops in a pre-VDI environment, don't assume that in a post-VDI environment the status quo will suffice. As part of the VDI project, the protection of laptops and desktop may be added to IT's list of responsibilities. One of the expected benefits of a desktop virtualization project is better data protection.
Assuming the virtualized desktops have to be protected, the issue becomes the manner in which VDI is rolled out. If it is a static state environment where the virtual desktops are always connected (the shift worker case), the master images simply need to be snapshotted and protected on a regular basis. If personalized local desktops or, worse, virtual desktops that are allowed to be disconnected (the knowledge worker case) are going to be used, then you have a challenge. All of these systems now need to be protected like any other standalone laptop would.
Most issues can be addressed by using synchronization software provided by either the VDI supplier or a third party that can update the unique parts of the individual personalized virtual desktops as they are changed. This may require additional storage capacity, which again needs to be accounted for. And these images need to be placed into a static state for the backup application to get a clean copy to protect.
The disconnected users do add one other wrinkle: protection while not connected. This is much less of an issue now than in the past. Most remote users connect into corporate IT resources multiple times throughout the day, and the synchronization software can send its updates while those connections are active.
When planning for desktop virtualization, it's typical to overlook planning for the additional VDI backup capacity (space and bandwidth) requirements. Make sure that you account for them. Then, understanding how the desktops are going to be used is the only remaining issue. The advantage of desktop virtualization is that desktops are now centralized, as is their storage, which makes data protection procedures far easier than having to back up a couple hundred local C drives.
About the author
George Crump is president of Storage Switzerland, an IT analyst firm focused on the storage and
virtualization segments. With 25 years of experience designing storage solutions for data centers
across the United States, he has seen the birth of such technologies as RAID, NAS and SAN. Prior to
founding Storage Switzerland, George was chief technology officer at one of the nation's largest
storage integrators, where he was in charge of technology testing, integration and product
selection. Find Storage Switzerland's disclosure
This was first published in August 2010