RavenDB in its core is a document database, and as such it is feature complete and very functional. A user may require additional functionality, such that is not implemented by the core, and this is where the bundles come in.
The following bundles are available out of the box, to extend RavenDB's capabilities in several common scenarios:
Compression - reduces the cost of I\O operations and data size on disk.
Built-in bundles can be selectively added to a specific database using Raven/ActiveBundles property in the database document. The documentation describing how to manage database configuration documents can be found here.
Beside the built-in bundles in RavenDB distribution package you can find other bundles that need to be placed in Plugins directory (see below for more information):
Authorization - allows to manage user groups, roles and permissions.
Installing a custom Bundle is as easy as dropping the assembly (and all its dependencies if any) into the Plugins directory of the RavenDB installation. Some bundles may also require some minimal configurations.
The path to the Plugins folder is configurable, see (configurations). By default it is (RavenDB server)\Plugins.
Included in the RavenDB distribution package are two scripts, enabling easy installation and update of Bundles.
Which you can use use to get new bundles or update the bundles you already have to a new version.
Note that most bundles have to be setup when you create the database, and they cannot be removed afterward. So consider carefully your bundles strategy. You can usually add a bundle and then configure its behavior (effectively turning it on/off) at runtime, but adding/removing bundles is something that can safely happen only when the database is created.