Prerequisites

Before migrating the Cloudera Manager embedded PostgreSQL database to an external PostgreSQL database, ensure that your setup meets the following conditions:

The external PostgreSQL database server is running.
The database server is configured to accept remote connections.
The database server is configured to accept user logins using md5.
No one has manually created any databases in the external database server for roles that will be migrated.
note
To view a list of databases in the external database server (requires default superuser permission):
```
sudo -u postgres psql -l
```
All health issues with your cluster have been resolved.

For details about configuring the database server, see Configuring and Starting the PostgreSQL Server.

For large clusters, Cloudera recommends running your database server on a dedicated host. Engage Cloudera Professional Services or a certified database administrator to correctly tune your external database server.