Log files can be used by both event logs and accounting logs and are stored on the compact flash device (cf3: on all platforms; also cf1: or cf2: on the 7705 SAR-18) in the file system. A log file destination is configured using the config>log>file-id log-file-id command. A log file destination is applied to an event log using the config>log>log-id>to file command and to an accounting file using the config>log>accounting-policy>to file command.
A log file is identified by a single log file ID, but a log file will generally be composed of a number of individual files in the file system. A log file is configured with the following parameters:
rollover: represents the length of time, expressed in minutes, that an individual log file should be written to before a new file is created for the relevant log file ID. The rollover time is checked only when an update to the log is performed. Thus this rule is subject to the incoming rate of the data being logged. For example, if the rate is very low, the actual rollover time may be longer than the configured value.
retention time: for a log file, specifies the amount of time the file should be retained on the system based on the creation date and time of the file. The retention time is used as a factor to determine which files should be deleted first if the file system device nears 100% usage.
When a log file is created, only the compact flash device for the log file is specified. Log files are created in specific subdirectories with standardized names depending on the type of information stored in the log file.