You might want to view event log files for the following reasons:

Once every week, the event log files are rotated. The /etc/log/backup file is renamed to /etc/log/backup.0, the /etc/log/backup.0 file is renamed to /etc/log/backup.1, and so on. The system saves the log files for up to six weeks; therefore, you can have up to seven message files (/etc/log/backup.[0-5] and the current /etc/log/backup file).