What format do sites like Facebook use to store data for personal profiles?

[Kurtis]

I'm pretty new to computer science and I recently started dealing with large sets of data stored in XML files. I've always wondered how Facebook and other networking sites store all the information associated with individual profiles (name, profile picture, wall posts, etc.) and I feel like XML is definitely not the best way to store so much information. I've tried finding information about it with google but haven't been having too much luck.

How do huge sites such as Facebook store and deal with so much data? I would really like to do some reading about this, so if you know of any good websites please let me know!

Thank you in advance!

[Moнѕιη]

Yes you are right. Facebook doesnt use Xml like structure. Its pretty old and not useful.
For the database, Facebook utilizes MySQL because of its speed and reliability. MySQL is used primarily as a key-value store as data is randomly distributed amongst a large set of logical instances. These logical instances are spread out across physical nodes and load balancing is done at the physical node level.

As far as customizations are concerned, Facebook has developed a custom partitioning scheme in which a global ID is assigned to all data. They also have a custom archiving scheme that is based on how frequent and recent data is on a per-user basis. Most data is distributed randomly.

PHP
Facebook uses PHP because it is a good web programming language with extensive support and an active developer community and it is good for rapid iteration. PHP is a dynamically typed/interpreted scripting language.

[kaboom_356]

Since facebook is written in PHP, I think they would store the information in a MySQL database. Try googling about facebook and MySQL.

Most large sites will store text and other information in a SQL database. Pictures and other large files will be stored as a reference location in the database (ex. profilepicture12345.jpg). But it is possible to store pictures in a SQL database.

Hope this helps, good luck!