The continuing evolution of VDI solutions

I have been following Brian Madden and his ongoing quest to understand virtualisation and its place in the enterprise for a few years now.

And, a little while ago he published an interesting article about a facet of virtualisation that I really had not focused on before.  Brian's article discussed the pros and cons of persistent versus non-persistent disk implementation in VDI implementations, and can be found on the TechTarget site here. 

As the article describes, there has been a "battle" between two different ways of deploying virtual desktops; persistent or non-persistent disks.

Brian defines persistent disk solutions as;

"With persistent disk images (also called "1-to-1"), there's a separate and unique disk image for each user. This means that if a user installs something or makes any other adjustments, those changes will still be there the next time the user logs in."

Most of us are probably familiar with this model, as it describes a common desktop virtualisation model delivered by VMWare. In contrast, non-persistent disk models are offered by companies like Citrix and are described as;

"(or shared images) disk images mean that multiple users -- dozens or even hundreds of them - all share the same master disk image. In this case, every time a user logs on, he or she gets a fresh copy of the disk."

The non-persistent (the "fresh disk" model) has advantages in user management and potentially lower disk costs but requires that all applications must be virtualized. Unfortunately, as this technology was developed, application compatibility was not that high for most applications, and as a result only around 70-80% of applications could be successfully virtualized. This lack of virtualisation suitability or limited application compatibility really limited the viability of these types of non-persistent disk VDI deployments.

With the rise of smart phone and tablet access and with more and more web-based applications developed and used in the enterprise, we may see fewer application compatibility issues and subsequently more deployments of the non-persistent disk  VDI model in the future.

Maybe it's now time to re-examine the merits of the non-persistent disk VDI model for your enterprise.