Working around new Distributed Databases

I am currently working on Distributed Database named COUCHBASE . Its really awesome and good to work with this . Here i given some features in couchbase server.

• Flexible Data Model
• Easy Scalability 
• High performance 
• Always on 24*365
• Fully supported SDKs for Java, C#, PHP, C, Python and Ruby.

 Problems with RDBMS :

Distributed Database :

Really lot of things to know about Distributed Databases.....