Executing the command yum to update the system, an error message related to rpmdb panic is shown.
rpmdb: PANIC: fatal region error detected; run recovery
This error is due to the system repository, in detail the server rpm database is corrupted and needs to be rebuilt.
To fix the problem is necessary to clean the yum cache.
# yum clean-all
Then the packages rpm database has to be cancelled and rebuilt using the commands:
# rm -f /var/lib/rpm/_db*
# rpm --rebuilddb
Trying to perform the system update once again through the command yum.
# yum update
During the process, the system verifies the database to check the consistency.
If the fix succeeded, the update process is completed installing latest releases of packages.
The system is now fully working again and updated to guarantee maximum stability.