Virtualisation is proving it can cope with high volumes of transactions on the Auto Trader website, which handles...
about one billion queries a month.
The site sits in a datacentre running 760 virtual machines (VMs) from VMware, configured with 22 VMs per physical server. These run the JBoss application server from Red Hat, the Apache web server, and a small number of back-end Windows servers. Auto Trader’s systems are built on standard open source and commercial software, using four-way AMD 64-bit quad-core PC blade servers from Sun.
Virtualisation has not hampered the site’s performance, according to Carolyn Bell, head of IT operations at Auto Trader. “After two years of rapid growth, we are now hosting 760 virtual servers on the same infrastructure, which no degradation in performance levels. This has resulted in a reduction in power consumption and improved carbon footprint by a factor of 30%,” she says.
Search is the critical application on the website. Auto Trader’s search facility allows users to run geospatial searches to find cars for sale. The search engine can refine search queries based on what the user has previously looked for. A search takes 150 milliseconds from when the first byte of information is loaded into JBoss to when the last byte comes out.
Auto Trader uses Endeca, a real-time search system which runs on 12 dedicated Sun machines and 30 VMware virtual machines. This configuration allows AutoTrader to maximise the speed of query processing, which is critical given the volume of queries it processes per month. “On average, we perform about one billion queries per month to Endeca from the JBoss search application,” says Peter Hanlon, chief architect at Auto Trader.
Trader Media Group, the company that runs Auto Trader, spent two years simplifying its website infrastructure. Previously, it used a variety of platforms to support different applications across the Auto Trader website, which posed a challenge to maintain in terms of cost, efficiency and particularly skills and training.
“We used to have a mixed environment with Microsoft ASP.net applications, four versions of the Tomcat open source application server, and two versions of JBoss, which made it difficult for us to standardise,” Hanlon says.
To create a standard operating environment, Hanlon embarked on a two-year change programme to move the core applications onto JBoss. “We formally managed 40% of the work by migrating our core systems, including the website, advert booking system, search and trading tools.” The remainder of the systems are being migrated as and when they need modifying.
The decision to undertake a gradual, low-risk migration was based on cost, resources and the need to maintain a competitive edge. The Auto Trader IT team migrated the different applications and elements of the site to a predetermined schedule.
To migrate the site in one go would have been a resource-draining project for the team of 60 developers. Such a “big bang” migration would have taken four months, stifling the continuous innovation and development of the site, said Hanlon.
Instead, Trader Media Group’s team developed a virtualised image, which means that it can quickly deploy JBoss servers as and when they are needed.