Hosting desktops or applications on servers located in the data center, and implementing centralized computing technologies is one of the best ways to cut IT costs while also improving security, reliability, productivity and efficiency. Both Citrix and VMware have high profiles offering their respective virtualisation solutions that enable centralisation. Yet if you are considering centralisation, do they offer your organisation a focused solution for your needs?
Centralisation technologies take full advantage of modern devices power and capacity to offer a number of significant benefits over the traditional desktop PC model. These technologies include Presentation Virtualization ( or Terminal Services/SBC) , Hosted Desktops (or VDI) and indeed Blade PCs – all, in their way, offer easier management, stronger security, improved regulatory compliance, and arguably lower costs for hardware, energy and administration, and improved disaster recovery. Each technology has its own advantages and disadvantages.
Presentation Virtualisation (PV, Terminal Services or SBC) is an architecture whereby applications are deployed, managed, supported and executed on a server and not on a client. Many users run in one operating system. Instead, only the screen information is transmitted between server and client. With PV:
- all the applications are installed on a single operating system, and are centrally managed – with other solutions , many desktop operating system s and application sets need to be managed
- PV hardware can typically support more users on the same hardware – because there is only one operating environment to utilise resources rather than many virtual desktop operating systems
- Therefore, PV is generally less expensive than hosted desktop virtualization. PV requires fewer servers and each PV server only requires one operating system license.
Hosted Desktops (HVD, or VDI) on the other hand is an architecture whereby a desktop that runs the applications is hosted on a virtual machine, and that virtual machine is hosted on a server in the data centre. One user runs per operating system. HVD has a number of advantages over:
- Support for personalisation and customisation – While PV is 1 server, 1 OS, many users – HVD is 1 server, many OSes, 1 for each user. HVD allows for unique applications and configurations per device/user if need be – (of course, in a managed way – otherwise you’ve just moved a cost problem from desktop to the data centre). For example, some users need IE8 and some IE7 and some IE6 – this is more straightforward to deliver with HVD than PV.
- You need to deliver a desktop OS, not a server OS – some applications have compatibility issues with server OSes. While newer applications tend not to be a problem, older apps such as 16-bit apps, DOS applications (and they do still exist and oddly tend to be the lynch pin of a multi-million currency-of-your-choice business’ whole operational process) can be a nightmare to deploy. Indeed, if you wanted to move to Linux apps, a PV Microsoft Windows server is going to be of no use to you.
- By extension…You can deliver multiple desktop OSes on the same infrastructure – HVD allows you to deliver Windows XP and Vista and Windows 7, or a Linux Desktop all within the same infrastructure.
Blade PCs is a PC in blade from housed in a rack enclosure, or a possibly simply a physical PC located in the data centre. The importance difference is that this architecture is intended to support one user per discrete device. This allows the device resources to be dedicated to the user – giving a more robust performance and stability over shared environments such as PV or HVD. Yet, many blade PCs will physically take up a great deal of space and will obviously require a greater investment in hardware.
Yet, as discussed in our Enterprise Desktop Strategy white-paper it is rare that an organisation can deliver an effective desktop strategy with one particular solution as, different technologies will give advantages depending on the demands of different types of users. As such, it is likely that an organisation will have to manage and maintain a range of services.
Citrix are driving their XenDesktop product offering. XenDesktop includes technologies to manage Presentation Virtualisation deployments, Hosted Desktop deployments and manage physical devices. Yet, XenDesktop is in fact two products combined: XenDesktop allows administration of HVD and Blade PCs, PV administration is provided by XenApp. It is true to say that the user experience of the service they are accessing is seamless and, with the HDX technologies, can include multimedia and 3D graphics. However, the two solutions are not managed in the same way – configuration, administration and devices to support those services are independent, there is an overhead in maintaining two different environments.
VMware – any flavour you like, as long its ESX
VMware‘s View is focused on delivering an enterprise HVD solution. The Tolly VMware VDI vs Citrix Xen Desktop made valid points -yet both offerings have now been enhanced and those points are less clear-cut. One of VMware View 4’s strengths is its integration with VMware’s server platform; and from a desktop centralisation viewpoint, the inclusion of the PCoIP display protocol now gives View users a far more desktop-like experience. However, while VMware View Unified Access allows users to connect, and administrators administer, the administration of PV is at best, rudimentary. Moreover, the only host environment supported by View is VMware’s vSphere for Desktops.
Citrix and VMware are not the only vendors offering integrated solutions for managing desktops in a centralised environment. A number of products have equivalent feature sets and can offer additional savings in reduced license costs, support for alternative environments and easier administration. Examples include:
- Ericom, provides Powerterm WebConnect Enterprise also provide access across all three technologies, with Powerterm WebConnect also supporting VDI services running on XenServer and can be used to support thin clients. In addition allowing each resource type to be managed and reported on Ericom have optimised the RDP protocol – their Blaze protocol reduces RDP bandwidth consumption by up to 25 times – improving performance across WANs and congested LAN environments.
- Quest Software offer vWorkspace – vWorkspace’s VDI support includes not only VMWare VirtualCenter, Microsoft Hyper-V, and Xenserver but other platforms such as Parallels Virtuozzo Containers. vWorkspace also includes remote printing optimisations, user profile management, lock-down policies and comprehensive load balancing for PV services. Quest also have their own optimised display protocol, EOP which has been optimised to provide a like-a-desktop display for remote users.
- Sytancia , offer AppliDis Fusion 4 which not only supports PV, HVD and Blade PCs. For HVDs not only is ESX supported as a platform but Microsoft’s Hyper-V as well. There is an integrated print solution, load balancing across PV servers, and reporting, auditing and logging. As with other solutions, users across all platforms are managed though a single interface, and users access their applications and desktops through a single portal.
Citrix and VMware do not fail to deliver desktop centralisation solutions that cover PV, HVD and centralised PCs. Yet, their feature rich products are not without fault: complexity of administration, high maintenance costs, reliance on a single hypervisor – all affect the cost of installation, and the time taken for you to make a return on your investment.
When considering centralised desktop deployment for your enterprise there is a tendency to focus on one or two particular solutions. In considering the best solution for your organisation, focus on the issues and goals you need to address in some instances you can solve those issues more cheaply or with less complexity with other solutions. Look to match a product’s features with your requirements rather than let the vendor focus on which features are best in their current release.
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