The use of server-based desktops, often referred to as a virtual desktop infrastructure (VDI), makes increasing sense for many organisations. Enabling greater control over how a desktop system is put together; centralising management and control of the desktops as well as the data created by the systems; helping organisations to embrace bring your own device (BYOD) and enhancing security are just some of the reasons why more organisations are moving toward the adoption of VDI.
However, in Quocirca’s view, there remain some major issues in VDI adoption. Our “Top 3” are detailed here:
- Management. Imagine that you are tasked with managing 1,000 desktops. Your OS vendor pushes out a new security patch. You have to patch 1,000 desktops. With VDI, at least you do not have to physically visit 1,000 desks, right? Maybe so – but it is still an issue, and with application updates coming thick and fast and the possibility that one single patch could cause problems with some proportion of the VDI estate puts many IT departments off such updates for fear of causing problems, so leading to sub-optimised desktops and possible security issues.
- Licencing. The phantom of better control when the desktops are all in one place in the datacentre can soon become less believable. Unless solid controls and capable management tools are in place, the number of orphan (unused but live) images can rapidly get out of control. Desktops belonging to people who have left the company do not get deleted; test images get spun up and forgotten about; copies of images get made and forgotten about. Each of these images – as well as using up valuable resource – needs to be licenced. Each requires an operating system licence along with all the application licences that are live within that hot image, even though it is not being used. Many organisations go for a costly site licence to avoid this issue rather than attempting to deal with it.
- Storage costs. The move from local OS and application storage on the desktop PC to the data centre can be expensive. Old-style enterprise storage, such as a SAN or dedicated high-performance storage arrays, has high capital and maintenance costs. A more optimised use of, for example, newer virtualised direct attached storage, virtual storage areas networks or software-defined storage (SDS) approaches using underlying cheaper storage and compute arrays from vendors such as Coraid or Nutanix can provide the desired performance while keeping costs under control.
So, does this mean that VDI is more trouble than it is worth? Not if it is approached in the right way. The use of “golden images”, where as few a number as possible of images are held, may hold the key.
Many VDI vendors that push this approach will start off with maybe four or five main golden images – one for task workers, one for knowledge workers, one for special cases and one for executives, say – but will then still face the problems of having these spin up and staying live on a per-user basis. Managing the images still requires either patching all live images, or patching the golden images and forcing everyone to refresh their desktops by powering them down and back up again – not much easier than with physical desktops. Dealing with leavers still needs physical processes to be in place, otherwise licencing still becomes an issue.
A better approach is to use a single golden image that can be used to automatically provision desktops on a per-user basis and automatically manages how software is made available and managed on an on-going basis. This requires an all-embracing golden image: it needs a copy of every application that will be used within the organisation present in the image – and it needs a special means of dealing with how these applications are provisioned or not as the case may be, to manage the licensing of each desktop. By virtualising the desktop registry and linking this through to role and individual policies in Active Directory, this can be done: as each user utilises their own desktop, it can dynamically be managed through a knowledge of what the virtual registry holds and what rights they have as a user.
The data held in the virtual registry also enables closer monitoring and auditing of usage to be made: by looking at usage statistics, orphan images can be rapidly identified and closed down as required. Unused licences can be harvested and put back into the pool for others to use – or can be canned completely and used to lower licencing costs with the vendor.
VDI is not the answer for everyone, but it is an answer that meets many organisations’ needs in a less structured world. If you have been put off VDI in the past for any of the reasons discussed above, then maybe it is time to reconsider. Today’s offerings in the VDI market are considerably different to what was there only a couple of years back.