When Panel starts performing a backup, it reports the progress to a log. Backup logs contain only general errors such as syntax errors (no or wrong command specified, invalid input parameters), runtime errors and unhandled exceptions, low disk space for backup, and so on.
Backup logs are stored in
/usr/local/psa/admin/PMM/sessions on Unix/Linux systems and
%plesk_dir%\admin\PMM\sessions on Windows systems, where
%plesk_dir% is an environment variable for the Panel installation directory on Windows systems. Each backup log is located in a separate folder that contains date and time of the backup in its name.
You can change the level of details included into logs. This feature is available only for scheduled backups and for backups made through command line. For more information on how to change level of details, see the Advanced Administration Guide for Linux and Windows.