Database Sharding Blog

Domas Mituzas has presented Wikipedia's scalability strategy at Velocity 2008 this week (presentation is available here). Mituzas is a Wikipedia performance engineer and database administrator and member of Board of Trustees of the Wikimedia Foundation. Mituzas is also a MySQL (now Sun) employee and was not shy about reminding people that the entire site is driven from a MySQL database.

There was a big emphasis in the presentation on achiving results with minimal resources because the Wikimedia Foundation is a non-profit organization with a comparitively small budget.

The Wikipedia scalability statistics are impressive - 80,000 SQL queries per second, 18 million page objects in the English language version of the site, 220 million revisions, and 1.5 terabytes of compressed data.

Wikipedia uses Database Sharding to set up master-slave relationships between databases, which are logically based on use cases and languages. Mituzas points out that the Wikipedia team only found out that they database architecture was an example of Database Sharding after they implemented it. Mituzas said MySQL instances range from 200 to 300 gigabytes.

Labels: Database Sharding, Scalability Architecture