Scalability issue - Drupal's Database Sharding? Federation?

Do you know a good tutorial/book about sharding/ federation of Drupal's database?
Does Drupal support that out-of-the-box?

• How to run a single installation/website with multiple databases?. Not a master/slave setup but moving some tables (cache?..) to a different database.
• How to run drupal with multiple databases. Each database will serve 100,000 (for example) users (the database will have those users' info, nodes.... )