Overview of System Logging

System events are classified into event categories. Using the CLI, you can determine which event categories to log. To fully utilize the logging facility, you need to understand log severity and log verbosity.

Log Severity

Log severity is a level that is assigned to an event or log message. Log severity levels apply to event categories, such as bulkStats, bgpRoutes, or atm1483.

The minimum severity of a log message for an individual category is described either by a severity number in the range 0–7 or a descriptive priority term, such as emergency or debug. The lower the severity number is, the higher the priority. See Table 3.

Note: Not every event category supports every severity level. For a list of event categories and the severity levels that each category supports, see Event Categories.

Table 3: Log Severity Descriptions

Severity Number

Severity Name

System Response



System unusable; shelf reset



Immediate action needed; card reset



Critical conditions exist; interface is down



Error conditions; nonrecoverable software error



Warning conditions; recoverable software error



Normal but significant conditions; nonerror, low-verbosity information



Informational messages; nonerror, medium-verbosity information



Debug messages; nonerror, high-verbosity information

Log Verbosity

The verbosity level determines the amount of information that appears in each message. You can assign the verbosity level for the log category. Verbosity levels can be any of the following:

Persistent Logs

Log messages can survive a system reboot. After a reboot, the system rebuilds the list of log messages. However, if the system detects any problems or has gone through a power cycle, the buffer is reset, and the log messages from the previous session are lost.

Log messages are not synchronized between primary and redundant SRP modules. During a switchover from a primary to a redundant SRP module, existing log messages are not transferred to the redundant SRP module.

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