Physical servers in virtualisation cull with Citrix XenServer
Top UK retailer Tesco has slashed the cost of operating a 1,500 strong Wintel server estate using virtualisation to cut data centre power consumption, free up floor space and reduce its IT carbon footprint.
An independent audit of the company’s twin data centres carried out in June 2008 had revealed its Wintel server assets were using 30% of the total power supplied. After a 12 month programme, during which it has virtualised two-thirds of its Windows servers, power consumption has now fallen to around 10%, the company’s IT service manager, Nigel Chubb told CBR.
“It called for a leap of faith, but we are very pleased with what we have achieved with virtualisation,” he said. We are two-thirds of the way through, and fully intend to continue with the programme. The business case for server virtualisation is a strong one, and we will be looking at desktop and Linux virtualisation next.”
The world’s number three retailer has deployed Citrix XenServer 5.0 across high density HP C Class blade servers, installed in an APC water-cooled hot aisle containment unit. Chubb said as a result, it has managed to turn off 200 old servers, has achieved better server delivery service levels, and improved IT’s stance in the support of business initiatives that need demonstrate speed to market.
The trigger to virtualisation was the lack of headroom in the Tesco data centres, and a need to upgrade a business critical real-time sales application.
Chubb said: “That application processes 1,500 transactions a second and is vital to the business, so we had to prove we could match or better a physical environment with virtualisation. We now know it gives us better performance than we had achieved on physical servers.” Server delivery times have been cut from weeks to a single day, he added.
The BizTalk-based application which is built around a large SQL database was lifted from physical servers and dropped into the virtualised environment using Novell’s Platespin PowerConvert software. All applications are delivered to Tesco branches using Citrix XenApp running on XenServer.
The businesses Exchange email service is another candidate for virtualisation, he added, and there are plans to reassess the disaster recovery strategy in the light of its positive experiences and base that around the technology also.
Strong governance is called for to avoid VM server sprawl, Chubb cautioned. “We have a policy that no Windows virtual servers can be built without approval.”
The virtualisation scheme was partially funded by drawing on a CEO-sponsored Green Fund, which supports Tesco initiatives that help address the company’s carbon footprint. Business projects that promise to contain or reduce it are backed by the scheme, provided they meet some very stringent targets.