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Blade PCs: the ultimate managed desktops

Roger Howorth ZDNet.co.uk

Published: 03 Jul 2007

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ClearCube: a client-only solution
ClearCube has been selling its blades for about seven years. Unlike HP and IBM, which concentrate mainly on blade server hardware, ClearCube is focused purely on providing blade solutions for desktop users.

Paul Dunford, director of channel sales for the EMEA region, says that ClearCube's approach sprang from an understanding of the problems associated with using conventional desktop systems. PCs are not very manageable or very secure, says Dunford, and many firms would like to reduce the costs and delays associated with sending IT staff to fix a malfunctioning PC located on someone’s desk. In many cases, it takes longer to get an engineer in front of a broken PC than it does for the engineer to fix the problem.

These problems can be bad enough for relatively small firms operating in a single building, but multi-site operations and challenging locations can prove a real headache. For example, sending an engineer off-site to fix a PC in a remote office is likely to be an expensive exercise. In many cases, the cost of downtime must also be considered: at a simple level, downtime means that people can't work as they would normally. But the cost of downtime escalates rapidly if the broken PC is, for example, located in an operating theatre or some other sterile area that can't be used until the PC has been fixed.

One of the key reasons for buying blade PCs is to minimise downtime. With blades, if the PC develops a hardware fault, a replacement can easily be switched into place — probably within a few minutes. Visits to users' desks should not be necessary.

The virtualisation effect
Although IBM offers blade PCs with virtualisation, HP does not currently recommend using virtualisation to host more than one desktop per blade. ClearCube, meanwhile, offers virtualisation as an option to reduce the cost per desktop.

Without virtualisation, each desktop user must be allocated one PC blade, which ClearCube reckons costs a typical customer about $4,000 (~£2,000) per user. However, virtualisation can be used to put up to 12 desktops on each blade. Even with the cost of the additional VMware ESX Server virtualisation software taken into account, ClearCube calculates that this brings the cost per seat down to about $1,200 (~$600). Of course, companies that are happy to use virtualisation could use fewer larger servers rather than many blades. However, virtualisation implies sharing processing power and memory between several users, and this only works well when most users are relatively inactive. With poorly configured virtualisation, a single user running CPU-intensive software could reduce the performance of other users' desktops. However, virtualisation tools such as ESX Server allow IT staff to apply 'reserves' and 'limits' on each user’s access to the CPU, so that each user gets guaranteed minimum and maximum levels of processing power.

Brokering
Although virtualisation reduces the cost per seat, it does raise the question of how users are allocated to blades. The simplest solution is for each user to be hardwired to a specific blade. However, this could make it tricky to switch users to a replacement blade in case of a fault. An alternative is to connect users to a broker, which then allocates virtual machines to users from its reserve. The Collier County project in the USA is an interesting example of this. Collier County Public Schools is a large education provider in Florida using HP technology to deliver virtual desktops to students. It uses a master virtual machine (VM) configured with Windows XP and a few infrastructure tools, including Microsoft’s SoftGrid application virtualisation. This VM is duplicated so that each user is allocated a copy of the master VM. SoftGrid then adds the required applications when the user logs in, and removes the apps again when the user logs out.

The video problem
Virtualisation may be the way of the future, but it seems that video and other highly graphical applications could keep us hooked on hardware for a while yet. This is because streaming video and other graphically intensive applications don’t work well when the display is more than a few metres from the PC. IBM, HP and ClearCube all agree that Microsoft’s RDP is not suitable for these types of application.

ClearCube’s Dunford also says that some of the company's older I/Ports had similar problems because the digital circuitry introduced small delays. However, ClearCube recently launched the I9400 Series I/Port, which includes Teradici PCoIP hardware to improve performance to the level where PC blades and I/Ports can now be used for graphics-intensive applications. Indeed, the I9400 is powerful enough to support four simultaneous displays. For its part, HP uses a proprietary protocol to handle graphics and says it is powerful enough to support full-motion video on four screens. IBM also uses proprietary hardware to improve the performance of video and graphics on its blade systems.

 

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