The RPM database holds information about all the RPM packages installed on your system. You can use this database to query what is installed, to help determine if you have the latest versions of software, and to verify that your system is properly set up, at least from a packaging point of view.

The RPM database itself is stored in the directory /var/lib/rpm/, and should contain files like the following:

These files make up the RPM database. The file __db.001 and similar files are lock files used by the RPM system. The other files are databases in Berkeley DB format. The most important file is Packages. The Packages file contains the header tag information for each package indexed by an index number for each package. This number slowly grows with time.

The other files, such as Name, Providename, and Group, exist to speed access to particular types of information. Treat your RPM database with care. Back up the files, especially after upgrading, installing, or removing packages.