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.
Critical application
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.
Standardisation
“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.
Low-risk migration
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.