Feature: hot tips for virtualisation

The programme will eventually see all Betfair’s mission-critical software development and quality assurance environments running on virtual servers.

Christopher Venning is head of IT at the Royal College of Physicians (RCP). He recently oversaw the implementation of 45 virtual servers hosted across seven HP blade servers and is in the process of virtualising 160 desktops using VMware’s VDI software.

The implementation focused on improving business continuity, reducing management overheads, and PCI security compliance. The college also has a cap on its power use because it is based in a residential area and needed to consolidate.

“We are based in Regent’s Park, and there is a limited amount of power we can draw. So to run 160 VDI desktop images, we had to use administration servers for additional power,” says Venning.

To understand the best route to successfully virtualising servers, IT chiefs must understand the requirements of the applications that will run on the virtual machines (VMs).

For organisations such as Comic Relief, planning was essential. It migrated most of its critical
applications to virtual servers, including its contact management, campaigns fulfilment, grants administration and finance systems based on Microsoft’s Dynamics GP software and an SQL-based data warehouse application.

Stefan Van Overtveldt is vice president of emerging technology and innovation at BT, which is moving toward a cloud computing environment that relies heavily on server virtualisation in the company’s datacentres.

Van Overtveldt agrees that effective planning and close examination of application requirements are key. BT has forged its own approach to this, dubbed the continuous migration process.

“For some applications there is no change at all, but for others you have to take a closer look at the application to figure out how it will work in a virtualised environment,” he says. “You have to look at the databases connected to them, the infrastructure they use, how they interact with the network and storage resources, then create a structured approach to migrating them.”

RCP’s Venning believes it is important to understand what services are running where and who uses them. “Some of the applications that you think will be tricky are actually a doddle. It is the general administration services that cause problems,” he says. “File and print services are hard to virtualise without disruptions to users and locally attached storage is hard to accommodate.”

One aspect of virtualisation that often catches people out is the strain it can put on the network. Putting 10 VMs on a single server greatly increases the data traffic to and from that server and any back-end solution has to take care of the increased I/O, caching and disk sharing, otherwise performance can be affected, says Colfescu.

“Everyone has invisible problems in the network but when you virtualise, those problems become visible because you are concentrating everything on one piece of hardware and bottlenecks occur,” he says.

Copyright © 2010 Computing

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