To keep up with growing consumer demand Carfax 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.
By Gary M. Lee and CTO CARFAX
As the most trusted provider of vehicle history information, CARFAX is used by millions of buyers and sellers each year to research used cars and light
trucks. As demand for used vehicle information rapidly increases, so do the number of visitors to Carfax.com. 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 (ADCs) to accelerate performance, cut data center costs and boost capacity over existing infrastructure.
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, millions of used car buyers turn to CARFAX for a Vehicle History Report before making their final purchase
CARFAX provides convenient, fast and dependable information and is one of the top five Web Sites that consumers rely upon for vehicle
information. With just the 17-character vehicle identification number (VIN), 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, Carfax.com logged nearly 80 million visits for access to our database of more than seven billion records. Meanwhile, our data centers
underwent server installations and refreshes about a dozen times a day.
Reputation for Service Fuels High Demand
We’ve staked our business on the delivery of fast, dependable access to valuable data about used cars. 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
To manage this enormous data model while accommodating traffic growth, CARFAX maintains nearly a dozen data centers across the country. 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.
Looking Beyond Load Balancers
We found the solution to meet our needs in the form of next-generation ADCs. An ADC 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
• 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.
• Support: In addition to a great solution, we wanted a partner with the capacity and desire to grow with us over the long term.
• Affordability: 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.
Dedicated, Niche Provider Outperformed Big Brands
CARFAX tested several ADCs. Ultimately, we chose a somewhat unconventional approach, opting for a smaller, dedicated vendor over big label
brands like IBM and Cisco. AppBeat DC from startup Crescendo Networks outperformed other solutions in a series of tests designed to demonstrate
performance and reliability.
Crescendo created a testbed with two different servers (one quad processor, one single processor) handling the most traveled URLs on the
Carfax.com 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/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.
To test reliability, the team pulled the plug on each of the servers under load. With the small server unplugged, the larger, 4-way server handled the
entire 3,500 transactions/second with 250 Mbps 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 8 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.
Reliable Performance, Peace of Mind in a Complete Package
Crescendo Networks 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 they backed up their 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.
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