Cole revealed that Twitter’s MySQL database handles some huge numbers — three million new rows per day, the storage of 400 million tweets per day replicated four times over — but it is managed by a team of only six full-time administrators and a sole MySQL developer.

via Twitter, PayPal reveal database performance – Software – Technology – News – iTnews.com.au.

Daniel Austin, a technology architect at Paypal, has built a globally-distributed database with 100 terabytes of user-related data, also based on a MySQL cluster.

Austin said he was charged with building a system with 99.999 percent availability, without any loss of data, an ability to support transactions (and roll them back), and an ability to write data to the database and read it anywhere else in the world in under one second.