Configuring Log File Archiving

For each log file logfile that you configure, the JUNOS logging utility writes a specified maximum amount of data to the file. The default maximum depends on the platform type:

• 128 kilobytes (KB) for J-series Services Routers
• 1 megabyte (MB) for M- and T-series routing platforms
• 10 MB for TX Matrix platforms

When the file reaches the maximum size, the logging utility closes the file, compresses it, and names the compressed file logfile.0.gz. The logging utility then opens and writes to a new file called logfile. When the new logfile reaches the configured maximum size, logfile.0.gz is renamed logfile.1.gz, and the new logfile is closed, compressed, and renamed logfile.0.gz. By default, the logging utility creates up to 10 archive files in this manner. When the maximum number of archive files is reached, each time the active log file reaches the maximum size the contents of the oldest archive file are lost (overwritten by the next oldest file). The logging utility by default also limits the users who can read log files to the root user and users who have the JUNOS maintenance permission.

You can include the archive statement in the configuration to change the maximum size of each file, how many archive files are created, and who can read log files. To configure values that apply to all log files, include the archive statement at the [edit system syslog] hierarchy level:

[edit system syslog]

archive {

    files number;

    size size;

    (world-readable | no-world-readable);

}

To configure values that apply to a particular log file, include the archive statement at the [edit system syslog file filename] hierarchy level:

[edit system syslog file filename]

facility severity;

archive {

    files number;

    size size;

    (world-readable | no-world-readable);

}

The number of files specified with the files statement can range from 1 through 1000. The maximum file size specified with the size statement can range from 64 KB (64k) through 1 gigabyte (1g); to represent megabytes, use the letter m after the integer. To enable all users to read log files, include the world-readable statement. To restore the default permissions, include the no-world-readable statement.