The desktop virtualization has many deployment models, and the enterprises classify these models based on various factors. Very broadly, there are two criteria for this classification:
- Operating System Virtualization
- Application Virtualization
Operating System Virtualization
Let us start with operating system virtualization first; which further sub divides the virtualization process into two:
1. Virtual Desktop Infrastructure (VDI):
VDI makes use of the server on which it has capability to store everything. This refers to the operating system, applications and user data, which may then be accessed by multiple clients. The complete technology and the control are centrally served, while the user has a full PC experience in parallel.
This kind of virtualization is suited where the operations are to be distributed with the restricted regulations. For example, it may be ideal for the contractors who work remotely for an Organization and are required to access the company’s applications within some restrictions.
VDI has an extensive deployment which is currently superior to any other technology providing remote access. This makes it an expensive choice against Session based virtualization, which costs approximately one-fourth of the total deployment costs incurred in VDI solution.
2. Session based Virtualization:
Imagine an environment where the user is connected to the remote desktop installation, and is able to send and receive the data based on the consecutive screenshots. This is the basis of session based virtualization method. With no control over the server resources, the user can execute simple processes and receive the output with the on and off tapping of the keyboard. The challenge with this method is that the session needs to stay active throughout. The powering-on of the server cannot be controlled at the client’s end. Citrix has been working in this direction with its recent software claiming to switch on the server from the client’s end though.
This virtualization method visibly has limited access, with no application or personalization control. With the very limited resources employed in the technique, the costs are approximately one-fourth of the total expenses needed for the VDI solution. This is good for the users who have simple monitoring needs on the server with minimal processing demands.
With session based virtualization, the user experience is extremely hampered when the multimedia or graphics rich data is to be transferred. The screen shots cannot match the fast transfer speed needed to display videos and animations. In other words, this method is as good as the Terminal Services in a VDI environment.
This refers to the applications which are executed on OS, even though those applications are not physically installed on the server. This technology provides an encapsulation for the applications which has major benefits.
The virtualization for applications can be achieved to varying degrees. For a full application virtualization, the virtualization layers come to play. These layers extract the necessary files from OS needed to execute the application and transfer them to elsewhere, usually a different computer. When the application tries to connect to OS, it is redirected to the different computer where all the needed components are present as a single file. For the application, it is like interacting with the OS as it always did, while it is completely aloof from the OS in technical sense.
- Many of the applications many corrupt OS if written poorly. This technology provides a protection by isolating OS from applications.
- Having an independent virtual machine may be expensive. With this kind of virtualization, the application uses only its needed resources from an already existing OS.
- It allows the applications to run in various environments, which are normally not suited to the applications.
- While the applications run in a different environment, OS migration becomes easier.
- Security is enhanced by isolating Operating system from the user driven applications.
Need of the Hour:
With the clear advantages that VDI solutions have over the session based virtualization methods indicate that it is the one to lead the market in near future. This cannot be realized until most of the Small and Medium Businesses (SMBs) shift their current systems to VDI environment. With cost as a basic constraint, it is not viable to be accepted too quickly.
This calls for the need to have a less expensive VDI solution. Perhaps, a few factors like the number of users or the memory space can be compromised to offer something more adaptable to limited budget enterprises. This solution with the true features of VDI, with ready compatibility to the future enhancements can bring revolution to SMBs. The main cost reduction can be brought in terms of administration costs. With the elimination of staff needed to monitor multiple systems and repairs on them, it is much easier to maintain a couple of servers within the Enterprise.
Further read on remote desktop services and misconceptions of data virtualization.