What do you mean by distribution as people often get confused. The following are things people often consider as distribution:
- Having some data on one site and different data on another site.
- Having a complete copy of data on all sites.
- Having more than one machine accessing the same data on a shared set of disks.
On reality, only the first of these points is distribution. The others aer replication and RAC.
Typically, to distribute data you divide it into several application areas and put each onto a different site. The other sites access the data they are missing via database links. The important point here is to locate the data at the site that will use it the most, thus reducing performance bottlenecks.
I rarely hear of people using distribution these days as most people centralise their databases.