Getting Vertical - Retail

Used Car Report Outfit CARFAX Updates Web Site with Crescendo ADCs

By TMCnet Special Guest
Gary M. Lee, Chief Technology Officer, CARFAX
  |  August 17, 2010

The economy has tightened the belts of car shoppers, and many are opting for pre-owned vehicles over new models to save money. To make sure they’re getting a reliable vehicle, many used car buyers turn to CARFAX for a Vehicle History Report before making their final purchase decision.

CARFAX is used by millions of buyers and sellers each year to research used cars and light trucks. The company offers one of the top five Web sites that consumers rely upon for vehicle information. With just the 17-character vehicle identification number, used car buyers and sellers have access to all the information reported to CARFAX for a specific car or light truck with a model year 1981 or later. 

Last year, logged nearly 80 million visits for access to its database of more than seven billion records. Meanwhile, its data centers underwent server installations and refreshes about a dozen times a day.

With Web site traffic growing at a rapid pace, alongside the demand for used cars and consumers’ tendency to turn to the Web for nearly all of their needs, managing traffic and reducing network connection has become a mission-critical priority. Like so many other information services, performance, scalability and reliability are essential to our success.

As demand for used vehicle information rapidly increases, so do the number of visitors to To better manage the load and ensure fast, reliable delivery of vehicle data, CARFAX recently upgraded from traditional load balancing technology to next-generation application delivery controllers to accelerate performance, cut data center costs and boost capacity over existing infrastructure.

With the traditional load balancers used to distribute load among the many servers in each data center nearing the end of their useful life, we began looking for a new way to accelerate and streamline our overall Web application infrastructure. We had simply outgrown the old technology that we felt could no longer effectively support the 50 to 100 million annual visits and close to a dozen data center installations and upgrades we handle each day.

We found the solution to meet our needs in the form of next-generation application delivery controllers. An ADC (News - Alert) not only balances load between different servers and data centers, but it also offloads processes from servers, including TCP management and SSL encryption and decryption. It became clear that replacing the outdated load balancers with advanced ADCs could dramatically accelerate data delivery performance, reduce our data center costs and boost available capacity in the existing infrastructure.

In our quest, we evaluated several ADCs for use in our infrastructure based on a specific set of criteria:


Performance and scalability

The chosen solution must not only ensure consistent performance and availability of our system, but also handle continued traffic growth with the same consistency and reliability.

Intuitive user interface

The ADC must be both easy to deploy and reconfigure to support our constantly evolving demand and data center transitions.

Reliable load balancing across data centers

We wanted to not only balance load between data centers, but also be able to take sites and applications offline for maintenance or upgrades without dropping users.


In addition to a great solution, we wanted a partner with the capacity and desire to grow with us over the long term.


 Budget concerns dictated that the solution must be cost effective and deliver an adequate and relatively quick return on investment, as well as demonstrate the ability to fulfill our needs well into the future.

CARFAX tested several application delivery controllers. Ultimately we chose a somewhat unconventional approach, opting for a smaller, dedicated vendor over big label brands like IBM and Cisco (News - Alert). AppBeat DC from startup Crescendo Networks outperformed other solutions in a series of tests designed to demonstrate performance and reliability.

Crescendo created a test bed with two different servers (one quad processor, one single processor) handling the most traveled URLs on the site and used a load generator to simulate DSL connections to the site.  The tests were designed to evaluate both performance under load and reliability when one server is dropped. The servers were not optimized or tuned in any way for the tests.

As a baseline, we tested performance of the two servers using an existing load balancer. The two servers together could handle 200 transactions per second before both servers began to fail.

Replacing the load balancer with Crescendo’s AppBeat DC, the two servers together handled 3,500 transactions per second — the maximum throughput of the load generator used — and ran at this rate for 45 minutes without any failed transactions. All the while, page load times were 20 percent faster than with the previous load balancer. (See chart on this page.)

To test reliability, the team pulled the plug on each of the servers under load. With the small server unplugged, the larger, four-way server handled the entire 3,500 transactions per second with 250mbps of traffic with zero failures. Even more impressive, when the larger server was unplugged, the small server alone managed 1,700 transactions per second without failure —better than eight times more than the baseline performance of both servers with a load balancer. In our tests, only AppBeat DC was able to provide this level of performance.

Crescendo Networks (News - Alert) outperformed other ADC solutions because of its specialized hardware platform and the unique manner in which it offloads and manages TCP connections for the server. AppBeat DC deployed on our network maintains the highest TCP connection ratio possible and shields our servers from the effects of heavy load.

Crescendo also impressed on other counts, including ease of use and cost, and it backed up its high performance solution with dedicated, expert support. When it came down to the final choice, Crescendo had the most complete package.

The Crescendo team created an application delivery product specifically for our environment. It eliminates the need to add more servers to handle demand and provides peace of mind without requiring our engineers to constantly monitor servers. We’re ensuring fast and reliable access to vehicle history information that our customers expect.

Gary M. Lee is CTO of CARFAX

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Edited by Stefania Viscusi