You can approach it as a standard backup and restore procedure:

1. backup your data directory (e.x.
2. backup your database (in case of the basic/out-of-the-box installation the database is stored within the data directory mentioned above)
3. backup your configuration (

Check out the following entries in Nuxeo Doc:

• Backup your Nuxeo using VCS: http://doc.nuxeo.com/x/IoAO
• Backup and restore: https://doc.nuxeo.com/x/IoAO

There are many ways for retrieving data, mostly depending on the format you need. You can use zip export, use nuxeo-core-io library for exporting in the format you want, or simply use the Content Automation system, having in an operation chain, an NXQL query to retrieve the data and apply a ftl transformation on the document feed that was produced as a result.