Virtualisation case study: ESB

23 Jun 2010

The Electricity Supply Board is the principal electricity utility in the State, employing 7,500 staff throughout Ireland across a number of vertically integrated business units. These include the customer supply unit which manages accounts for customers, ESB Networks which maintains the infrastructure, and ESB International which invests in energy and engineering projects around the world. ICT Group is the company that provides IT and telecoms to the internal business units within ESB.


The ESB has one of the largest IT infrastructures in the country, with 1,000 servers and two data centres – one in North Dublin and the other in the south of the city. The company is constantly expanding, adding more than 50 new server deployments every quarter, according to Gabriel O’Mara, senior VMware administrator at the ESB.

ESB has run VMwares ESX since 2004. “We’ve found it’s reliable and lets us make really good use of our hardware. We have around 60 VMware hosts, hosting almost 600 virtual machines, a mix of test and production servers.

“We are deploying more virtual machines than physical ones now. If someone requests a new server that’s not virtual, they have to make a business case for it.

“Pretty much we have virtualised every application we use and have had problems with virtually none.

“We made up to 50pc savings in upfront server hardware and decreased our data centre space requirement by up to 75pc through savings in rack space. That’s important because we rent our data centres.

“We have also seen up to a 75pc reduction in power consumption at our data centres and decreased software licensing costs.”

The benefits are faster deployment – gone from six to eight weeks needed to deploy a server, down to two or three days. High availability is now standard, if the host machine fails, all the machines are restarted on other machines within three minutes. “That has only ever happened to us once,” added O’Mara, who said the ESB is currently running at 500 days uptime.

“We are consolidating 25 standalone Oracle servers onto a four-node ESX cluster, reducing its database licence requirement from 50 to 16.

“We have reduced our carbon emissions by more than 1,000 tonnes in the last year.

“Eighty-five per cent of our physical servers were less than 10pc utilised.”

Next step for the ESB is to pilot virtual desktops, involving 100 users that are using VDI clients to remove the reliance on physical client machines. This will be especially useful for the company’s business continuity planning, said O’Mara.

The energy supplier is also upgrading to VMware’s ESX 4. “It has a much smaller attack surface for malware, Trojans and so on,” said O’Mara.

“My advice is, go for it. Virtualisation is a great technology and it will do everything for you.

“Be aware that you should only deploy critical machines on clusters, and don’t use any hardware that hasn’t been certified as compatible by VMware.

“We plan to ultimately have 200 physical servers and 1,000 virtual machines in the future. Virtual machines will outnumber the physical hardware by a factor of five to one.”