Troubleshooting Guide

Log file transfer
The system logs contain important information for debugging and maintaining the switch. After the
current log file reaches the configured maximum size, the system creates a new log file for logging.
The system transfers old log files to a remote host. You can configure up to 10 remote hosts, which
creates long-term backup storage of your system log files.
Of the 10 configured remote hosts, 1 is the primary host and the other 9 are redundant. Upon
initiating a transfer, system messaging attempts to use host 1 first. If host 1 is not reachable, system
messaging tries hosts 2 to 10.
If log file transfer is unsuccessful, the system keeps the old log files on internal flash. The system
attempts to transfer old log files after the new log file reaches the configured maximum size. The
system also attempts to transfer old log files periodically (once in one hundred log writes) if the disk
space on the flash is more than 75% full.
You can log system log messages to external system log hosts with both IPv4 and IPv6 addresses
with no difference in functionality or configuration.
With enhanced secure mode enabled, authorized users can use SFTP to transfer files to a remote
server with the content encrypted.
You can specify the following information to configure the transfer criteria:
• The maximum size of the log file.
• The IP address of the remote host.
• The name prefix of the log file to store on the remote host.
The system appends a suffix of .xxxxxxxx.sss to the file name. The first six characters of the
suffix contain the last three bytes of the chassis base MAC address. The next two characters
are 01. The last three characters (sss) denote the sequence number of the log file. For
example, if you configure the name prefix as mylog, a possible file name is mylog.
90000001.001.
• The user name and password, if using File Transfer Protocol (FTP) for file transfer. Use the
following commands to configure the user name and password:
boot config host user WORD<0–16>
boot config host password WORD<0–16>
Be aware of the following restrictions to transfer log files to a remote host:
• The remote host IP address must be reachable.
• If you transfer a log file from a host to the system, (for example, to display it with a show
command), rename the log file. Failure to rename the log file can cause the system to use the
recently transferred file as the current log, if the sequence number in the extension is higher
than the current log file. For example, if bf860005.002 is the current log file and you transfer
bf860005.007 to the system, the system logs future messages to the bf860005.007 file. You
can avoid this if you rename the log file to something other than the format used by system
messaging.
• If your TFTP server is a UNIX-based machine, files written to the server must already exist. For
example, you must create dummy files with the same names as your system logs. This action
is commonly performed by using the touch command (for example, touch bf860005.001).
Log and trap fundamentals
January 2017 Troubleshooting 44
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