Understanding Desktop Virtualization – Advantages & Disadvantages

Desktop Virtualization is about moving your desktop session and hosting it on a server, from where you can access it. Looks more like SaaS and Private Cloud, doesn’t it? This article gives a short introduction to Desktop Virtualization along with reasons as to why a company should (or) should not look at implementing it.

What is Desktop Virtualization?

A user logs-in to the network using his Corporate Directory user-name and password in his Computer – He gets his desktop. He then goes to the conference room with his laptop. Since there is some time for the conference to begin, he logs-in to the network using his user-name and password – He still gets his desktop. He goes home, but since a client is asking for an important piece of information, he needs to access his desktop. He connects his home PC to the Internet, establishes an encrypted session back to the company network and logs-in with his user-name and password – He gets his desktop with all his applications and data, again!

So essentially, Desktop Virtualization provides users with an operating environment that is separate from their local physical system. In the most common form of Desktop Virtualization, this is provided on servers in the company’s Data Center. The Operating System, Applications & User Data which are normally loaded on to the user’s computer, are now hosted and rendered on servers in the company’s Data Center and the user can access his desktop environment from anywhere. That’s the purpose of Desktop Virtualization.

So, Desktop Virtualization solution consists of the Servers, Virtualization Software on the Servers & Virtual Image on the desktops. Well, not only Desktops – It could be Laptops, Thin-clients and even smart phones. Generally, you pay for the Virtualization Software as well as license costs for the total (maximum) number of concurrent virtual desktop sessions expected at any point of time in the organization. Other than this, you need to pay for Operating System License Costs (For Windows, you may need to purchase Software Assurance licenses over the bulk licenses already purchased for the OS. For new machines you can purchase their Virtual Desktop Access License (VDA) which is a subscription based model with yearly charges).

Advantages of Desktop Virtualization:

• Accessing your desktop environment from anywhere through LAN, WAN (Including broadband from home), etc at any time you want.
• Most of the Desktop Virtualization (DV) solutions support local USB drives, local printing & local graphics acceleration (Remember, that the desktop & applications are rendered on a server, and not on the local computer).
• Centralized Operating System & application updates / migration can be done regularly by a trained technician at the data center collectively for a group of virtual desktops.
• Desktop Virtualization solutions integrate with corporate directories like Active Directory/ LDAP etc, and User Access Policies can be applied to all users based on their role, location, type of device, etc.
• Desktop Virtualization enhances security as the administration is centralized – Antivirus/ Firewall policies can be applied and monitored from the data center. The applications that can be accessed and run by the users can be restricted and even tracked.
• Faster, reliable and easier backup/ recovery of all the user data is possible due to centralized hosting and administration.
• Desktops/ Laptops/ Thin-Clients/ Smart Phones and many more devices could be used by the authorized users (where ever they are) to access the centralized hosted applications.
• Desktop Virtualization calls for some integration with Server Virtualization as the DV software runs on the servers and keeps the individual computer sessions isolated from each other.
• With some DV vendors, a virtual desktop client can be downloaded to their computers which allows them to work when network connectivity is not available & it synchronizes with the server as soon as it connects to a network.
• Generally DV vendors have optimized protocols for better performance of the Desktop-Server connections in both LAN as well as WAN environments.
• For applications that require heavy CPU processing, the performance with Desktop Virtualization might be better, as the applications are now being processed by the heavy-duty server processors, than the desktop processors.
• Users can just call any application and any Operating System to their desktop (with just a click) and shift between multiple such sessions almost instantaneously.
• Desktop Virtualization software generally has settings to allow administrators to allocate / limit server resources that can be used per user, so that an individual user doesn’t over-consume resources.
• Desktop Virtualization is offered as a cloud based service by some companies, which could be adopted by SMB’s on monthly payment basis (without upfront investment costs).

Disadvantages of Desktop Virtualization:

• Desktop Virtualization is Cap-ex intensive. One needs to buy the Desktop Virtualization Software/Licenses, Servers, Centralized Storage infrastructure, Upgrade Network infrastructure to support more bandwidth, etc in addition to buying computers/ thin-clients for each user.
• There is no reduction in the number of end-user client machines (computers) that are needed in the network.
• The licenses for Operating Systems, applications etc, still needs to be bought for each user (mostly) and there is no reduction of costs there.
• The thin-clients are sometimes as expensive/ more expensive than individual computers as, with huge volumes computer prices plummet drastically as they are manufactured and distributed in bulk quantities.
• The network infrastructure needs to handle all that extra bandwidth that Desktop Virtualization is going to introduce. Otherwise, it has to be upgraded. The WAN links need to have sufficient bandwidth to handle all those remote DV users, as well.
• If the bandwidth on the remote end is not sufficient/ if there is congestion in LAN, the display quality may not be as good (when images are streamed from server) as processing and viewing applications right from a desktop.
• Its difficult to handle graphics/ high-definition video with Desktop Virtualization. But there are some work-around methods that vendors follow to overcome this limitation (Including having local graphic acceleration cards, rendering graphical applications on the desktop, etc).
• Some vendor Desktop Virtualization solutions work only with their Server Virtualization counterparts, hence limiting the choices for the customers.
• There is a limit to the number of Operating Systems that can be supported by Desktop Virtualization products.

There is another type of desktop virtualization where a desktop computer (Processor, RAM) is shared to create many more desktops by just adding monitors, keyboard, mouse and low cost access devices – Click here to read about the same.

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