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Virtual desktop infrastructure (VDI) deployments can bring definable benefits to any organisation large or small, but to maximise those VDI benefits, great care must be taken when navigating marketing information and sales presentations -- there is important information that vendors or resellers may omit.
Assessing whether to introduce a thin client platform or to continue with or change your existing platform, and then translating this to business decision-makers, can be challenging and time consuming.
Where to start: Research software virtual machine software vendors
In August 2008, IDC published its Worldwide Virtual Machine Software 2007 Vendor Shares report, showing internation virtualisation revenues for all key software vendors. Unsurprisingly, VMware headed the list with $1,29 billion, with flavours of Unix from IBM and Hewlett-Packard following closely behind. More of a surprise was Parallels, showing virtualisation revenue of $90 million and Microsoft showing $5 million. Other vendors with virtualisation offerings, such as Sun, Citrix, Oracle, Novell and Virtual Iron, only contributed $43 million in total.
Helpful hint: Hardware vendors like HP are aligning themselves with VMware and Citrix to offer specific products on their own part codes, giving the impression that only two key offerings exist. Microsoft's Terminal Services (Remote Desktop Services, as it is now known) or Virtuozzo Containers from Parallels are also very strong contenders in a Windows environment.
Desktop operating system licensing
For many, the rules surrounding the Microsoft Virtual Enterprise Centralised Desktop (VECD), which seemingly must be purchased for VDI implementations, can be confusing. For Citrix users, the subtle difference between hosted and offline implementations can determine whether a VECD is applicable or not.
Helpful hint: Streaming applications to an existing desktop avoids VECD. Parallels Virtuozzo Containers uses the data centre variant of Microsoft's server family allowing unlimited virtual desktops to be created without incurring any VECD cost.
Calculate true VDI costs and savings
In assessing the true cost of owning a VDI environment, the additional costs not quoted by a solution provider should be identified and understood.
Helpful hint: Software vendors provide return on investment (ROI) calculators to allow you to explore the savings that their product will provide, but the calculators often overlook the increase in indirect costs that products will generate. For example, any investment in additional server hardware could increase your power and cooling bills, but this could be offset against savings made by introducing more power-efficient thin client hardware to replace existing PCs.
Software licensing concerns
Consideration needs to be given to the type of software license currently in place. Many traditional desktop environments were purchased with OEM versions of software as vendors like Microsoft strived to gain and maintain their market share. Helpful hint: Not all OEM software is transferrable into a VDI licensing model. For example, all OEM versions of Microsoft Office will need to be replaced with new purchases on acceptable licensing programs. This can add a considerable sum to the initial project costs.
The importance of server ratios with a virtual desktop infrastructure
For a VDI solution to work effectively, it must be powered by an appropriate number of servers. Software vendors' estimates of themselves and each other vary widely. For example, on a single server/blade containing two quad-core processors and 32 Gb RAM, VMware's vViews can average 50 users, whereas Parallel's Virtuozzo Containers will average 100. Citrix can provide replication of the user workload through its Edgesight product, but identifying the typical workload is a challenge in itself.
Helpful hint: Establishing the exact number can only be confirmed by running a live pilot through a full month period, taking into account various processing demands.
Connecting the remote user with VDI
In principle, VDI is ideally suited for remote user connectivity. The offputting aspect is the quality of connectivity and the associated screen speed. Conflicting evidence pitching RDP- and ICA-based connections against each other can often ensue.
Helpful hint: Before considering which option suits your organisation, consider the additional infrastructure that will be required to make that connection available. For example, connecting in a Citrix environment will require a connection device, CAG or Netscaler, and maybe a failover device, as well as an license upgrade or the purchase of another license altogether. Remote access can add 10 to 20 percent onto a project cost.
Server platforms options are numerous
One success factor in a VDI implementation is the speed of the user's desktop -- hence, the speed of the supporting servers is critical to a project's success. Tesco's recent decision to choose Citrix over VMware has illustrated that platforms other than VMware can be deployed in enterprise mission-critical environments.
Helpful hint: VDI technology vendors like VMware and Citrix have complimentary server virtualisation products, which can add additional management and capability benefits.
Minimising TCO and maximising user productivity
VDI costs per user in larger companies will be typically lower than in smaller companies since the cost of the server infrastructure and the clients must be divided by the number of users.
Helpful hint: If total cost of ownership (TCO) is to be maximised, the larger the number of users being migrated to VDI, the larger the saving per user. For VDI users, the distraction of a desktop, with its ability to add devices and software, is removed, since the desktop and its components are centrally controlled.
Printing with VDI
Allowing a user to print as they did in the desktop environment is fraught with difficulty. Vendors have addressed this by partnering or purchasing technologies that address the adequacies of their base product. For example, ThinPrint is a specialist complimentary product that addresses many user needs. ThinPrint has positioned its products to work with RDP, TCP/IP and ICA protocols, meaning that printing needs can be addressed independently of the chosen VDI vendor.
Helpful hint: Remember that the server infrastructure that supports this sits within the data centre and therefore will add another vendor to the supported products list.
Don't forget Microsoft
Recently, Microsoft further strengthened its VDI intentions by announcing VDI Standard Suite and VDI Premium Suite offerings. The Standard Suite includes the core products and CALs required to enable and manage a low-complexity VDI environment. The Enterprise Suite adds an RDS CAL for non-VDI use and App-V for RDS sessions.
Helpful hint: For years, companies have successfully delivered thin client infrastructure using Terminal Services. With Microsoft's increasing focus on virtualisation products, upgrading an existing infrastructure may provide more cost benefits than displacing existing installations with VMware or Citrix.
Andrew Cross is the sales director at reseller Sol-Tec and a contributor to
This was first published in October 2009