IMPORTANT: this feature is available since Release 4.1.
You can have multiple CMS databases sharing the same web design and selected content documents, but having different content documents, too.
With that you can easily create multi language sites: you create the web design documents (stylesheets, components, templates etc) only in one master CMS database, and create different, language dependant content in the slave databases.
Basic logic
One CMS database is chosen as 'master', for example the english version of your site. Then you create other CMS databases and configure them as 'slave'.
Then, by executing a manual action or on a daily basis, all web design related documents, selected content documents and selected configuration settings are copied from the master to the slaves.
As a result you have multiple CMS databases having the very same web design, but different, language dependant content.
When you change the web design in the master, it is being copied to the slaves automatically.
Setup
Create your first CMS database, create some web design, configure it, create some content.
Then create another CMS database and go to 'Administration' -> 'Master/Slave'. Enable the checkbox and choose the first database as master.
Then click on 'inherit design and selected content' to initially copy all the stuff from the master. If you like enable the 'automatically copy every night' checkbox so that the copying is being done automatically.
Make sure that the agent '(slaveCopyFromMaster)' is enabled.
What is being copied
The following documents are being copied from the master to the slave:
Areas
Stylesheets
Components
Templates
Content types
Navigators
result templates
free data
ressources -> files when thy have the option 'copy to slaves' set
ressources -> JavaScript? code
content documents having the property 'copy to slaves' setNo configuration settings are being copied, you have to configure 'administration' and 'customizing\basics' in every slave.
Copying selected content documents
In the master, enable the property 'copy to slaves' in the 'basics' tab on a content document. Then this content document will be copied to slaves, too.
This is useful for special content documents needed for the web design or for other content which should be equal in all databases.
You can set this property by the content type, too.