Just went through a presentation on EBay. It talks about how they maintain a balance between scalability, performance, cost and features. Here are some of the stats that will wow you:
- 212,000,000 registered users (I am one of them).
- Over 1 Billion photos
- Over 1 Billion page views everyday
- 105 million listings on the site
- Stores over 2 Petabytes of data (1,125,899,906,842,624 bytes)
- 3 Billion API calls a month
- 300+ features per quarter
- Roll out 100,000+ lines of code every two week
- 26 Billion SQL query executions / day
- Always on – over 99.94% available
Impressive, isn’t it? btw, here is the presentation.