Each log message that is generated by a Cisco IOS device is assigned one of eight severities that range from level 0, Emergencies, through level 7, Debug. Unless specifically required, you are advised to avoid logging at level 7. Logging at level 7 produces an elevated CPU load on the device that can lead to device and network instability.
The global configuration command logging trap level is used in order to specify which logging messages are sent to remote syslog servers. The level specified indicates the lowest severity message that is sent. For buffered logging, the logging buffered level command is used.
This configuration example limits log messages that are sent to remote syslog servers and the local log buffer to severities 6 (informational) through 0 (emergencies):