10 years ago

The Evolution of AOL’s Web Site Architecture

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 AOL's front-end servers are virtualized, but its database servers are onsite.

More than just being big and an internationally recognized technology corporation, AOL is also a company that other businesses, especially small- or medium-sized enterprises who are looking for high availability for their Web sites, look up to and look into.

With unique monthly visits of more than 35 million from the United States alone, we can say that AOL’s homepage has more visitors than top-rating television programs like the Today Show and Good Morning America have viewers.  So how does AOL.com handle all that traffic?

Before we get into that, let us make it even more impressive by throwing in the numbers.  AOL’s architecture is now more than six years old, having been built from scratch five times in the past.  The whole system is run by approximately two dozen people.  Yet, AOL provides 99.999% availability even if it does get approximately 5 daily page views per visitor.

Now can you replicate AOL’s system?  Yes! What do you need to know?

1. Redundancy.  You will need to make sure that everything in your system is redundant.  This way, no matter what goes down, what goes wrong, or what is undergoing maintenance, your customers will still be able to access what they need.

2. Avoid shared infrastructures.  If you have more than one Web site, then resist the temptation of having these sites share the infrastructure to deliver each site’s pages.  Problems on one property should not affect the others.  If one site goes down, all the others should be able to remain accessible.  AOL does this by putting up downstream systems.  If one of the sites depended on AOL.com, these sites would have a protection service that would tap into downstream systems.  The downstream systems do not get requests from all over the Internet, but for a select few servers.  What’s more, responses from these downstream services are cached.  AOL also replicates its databases to the point that each site would have its own copy of the databases.  All in all, the only shared infrastructure is the authentication and networking.

3. Monitor.  All of the applications that AOL has are actively monitored by AOL’s own software tool.  This proprietary tool monitors CPUs, interfaces, file systems, Web traffic, response times and other types of data & activity.

4. Databases.  AOL’s front-end servers are virtualized, but its database servers are onsite.  This is because AOL pages are very dynamic and rely heavily on the database.  The company runs MySQL 5, and these servers are then replicated.  There are currently 30 slave replicas spread over the company’s 3 datacenters.

5. Caching.  Furthermore, everything from the Content Management System, database responses, JSP codes and static assets are all cached.

Need High Availability for your Web site as Well as MySQL and Oracle Consulting Services?

If you want to have 99.999% availability for your Web sites, then be sure to call (817) 377-1144 and talk to Four Cornerstone.

Four Cornerstone has a team of Oracle experts who breathe and eat Oracle. We also have experts who specialize in MySQL, Oracle SOA, Oracle Linux, among others.  We can help you know the Oracle software you need in order to implement something like what AOL has and we give other Oracle consulting services.  From determining what you need and what software has the functionality you need, to getting the necessary license, and then installing your software, and to training your staff on how to use these software.

Contact Four Cornerstone now!

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