Drupal sites run as a result of an interaction between four components:
the database
the core codebase
the contributed modules and themes directory, along with the
settings.phpfilethe files directory
In practice, we will back up the modules, theme, and files directories together, as they all reside in the sites directory. However, when it comes to updating the site, it is helpful to think of them as separate from one another. When upgrading sites, we treat the core codebase, contributed modules, and contributed themes in different ways.
Also, as part of your backup and maintenance strategy, you should create a document that lists all of the critical usernames and passwords for your site.
This list of critical data includes:
Username and password of UID1 on your site.
Username, password, and database name of your database.
Username and password for FTP (or preferably SFTP) access to your site
Username and password for SSH (or shell) access to your site.
At the risk of...