Avocent CCM Managing Port History, Using the local history buffer

Chapter 3: Operations 33

Managing Port History

Each CCM appliance serial port has a circular history buffer that contains the latest 64K bytes of data received from the attached serial device. You may enable the NFS feature, which will write buffered data to a file on an NFS server. Port history information may be useful for auditing and troubleshooting.

Using the local history buffer

The history buffer begins filling with data received from attached devices upon completion of CCM appliance initialization, even if no user is connected. When you connect to a serial port, the data that was received from the attached serial device prior to the connection is available in the buffer. Once online, new data continues to be stored in the buffer. You may choose whether to display the history buffer’s content automatically when you connect and whether to keep or discard the history buffer’s content at the end of a session.

When more than 64K bytes of data are sent to the history buffer, data at the top of the buffer is discarded to make room for the new data. As a result, the buffer always contains the most recent 64K bytes of port history.

Using port history mode commands

Once you are in port history mode, you may issue the commands listed in Table 3.6. Only the first letter of the command is required.

Table 3.6: Port History Mode Commands

Command Description

Bottom	B sets the view location to the bottom of the file minus 23 history display lines, if available.
Clear	C clears the port history buffer.
Help	H displays a summary of the port history commands.
Next	N increments the current history display line by the number of lines per page and outputs a
	new history display page.
Prev	P decrements the current history display line by the number of lines per page and outputs a
	new history display page.
Quit	Q returns to the normal CLI.
Resume	R leaves port history mode and CLI mode and resumes the session with the attached serial device.
	This single command is equivalent to sequentially using the Quit and Resume commands.