A database server is basically a central location where you host your database files. There is no question that in any web application, social websites or web 2.0 sites or whatever, that the database server is like the heart and you can’t live without it. And in recent years, thanks to open source, lots of companies and social sites has chose to stick with MySQL for their database. I think the reason is obvious.
1. Cost and Scalability
I like their presentation on their so called “scale out” technology and a brief real life case of other companies/partners who had adopted the technology.
What is Database Scale-Out?
Scale-Out is a modern computing architecture that enables organizations to improve application performance and scalability on an incremental, as-needed basis by adding multiple replicated database servers on low-cost commodity hardware. This is in contrast to a Scale-Up approach, which requires organizations to make a large up-front investment in more expensive and complex server hardware and database licenses in order to add capacity.
In the online world, many of the largest and fastest-growing companies use MySQL to cost-effectively Scale-Out their successful businesses, saving millions of dollars over high-cost proprietary technology — including Google, Yahoo, craigslist, Ticketmaster, Wikipedia, YouTube, and Evite/Citysearch.
Be ready to be impressed of how some popular companies rely on MySQL, especially several ecommerce and social sites which have a huge lot of traffic and thus need to serve a high read-to-write ratio. More info here