Archiva uses an external database for two purposes:
Generally, it is unnecessary to configure anything - the built in embedded database is suitable for the artifact management, and if an external authentication mechanism is not needed, the user database.
However, it is possible to configure an external database as needed.
Archiva uses JNDI data sources to locate the databases to use:
Configuring an external database for either or both of these sources depends is configured in jetty.xml if you are using the standalone installation, or in the application server configuration if you are using the web application installation.
By default the archiva and users databases are stored in the databases directory where Archiva is installed. To change the path, just edit all instances of the "DatabaseName" property in conf/jetty.xml (see below).
Note: If you are using MySQL as your database, Archiva fails when the users database created is initially set to UTF-8 for the character encoding. As a workaround, set the database to UTF-8 encoding after it has been populated. See MRM-1373 for more details.
...
<New id="archiva" class="org.mortbay.jetty.plus.naming.Resource">
<Arg>jdbc/archiva</Arg>
<Arg>
<New class="org.apache.derby.jdbc.EmbeddedDataSource">
<Set name="DatabaseName">/path/to/database/directory/archiva</Set>
<Set name="user">sa</Set>
<Set name="createDatabase">create</Set>
</New>
</Arg>
</New>
<New id="archivaShutdown" class="org.mortbay.jetty.plus.naming.Resource">
<Arg>jdbc/archivaShutdown</Arg>
<Arg>
<New class="org.apache.derby.jdbc.EmbeddedDataSource">
<Set name="DatabaseName">/path/to/database/directory/archiva</Set>
<Set name="user">sa</Set>
<Set name="shutdownDatabase">shutdown</Set>
</New>
</Arg>
</New>
<New id="users" class="org.mortbay.jetty.plus.naming.Resource">
<Arg>jdbc/users</Arg>
<Arg>
<New class="org.apache.derby.jdbc.EmbeddedDataSource">
<Set name="DatabaseName">/path/to/database/directory/users</Set>
<Set name="user">sa</Set>
<Set name="createDatabase">create</Set>
</New>
</Arg>
</New>
<New id="usersShutdown" class="org.mortbay.jetty.plus.naming.Resource">
<Arg>jdbc/usersShutdown</Arg>
<Arg>
<New class="org.apache.derby.jdbc.EmbeddedDataSource">
<Set name="DatabaseName">/path/to/database/directory/users</Set>
<Set name="user">sa</Set>
<Set name="shutdownDatabase">shutdown</Set>
</New>
</Arg>
</New>
...While it is a good idea to back up both databases, it is not strictly necessary to back up the repository database on a regular basis. Should any data loss be suffered, this database can be regenerated by deleting it's contents and re-scanning the repositories.
If you are using the default user security mechanism, it is important to back up the users database on a regular basis to ensure that the user passwords and information are not lost in the event of corruption. With the default embedded storage this is simply a matter of making a copy of the database directory on the filesystem. If you have configured an external database as the source for user information, please refer to your database documentation for backup instructions.