Dell M6220 User Configuration Manual page 212

After you enable email alerting and configure the mail server and recipient
email address, log messages with a severity level of emergency and alert are
sent immediately with each log message in a separate mail. The email subject
is "Urgent Log Messages." Log messages with a severity level of critical, error,
and warning are sent periodically in a single email. The email subject is "Non
Urgent Log Messages." Messages with a severity level of notice and below are
not sent in an email.
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Monitoring and Logging System Information