How to Dump Install Logs to the Serial Port of the Virtual Machine

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Revision as of 06:45, 29 July 2011

Go to: Implementing Virtualization Deployments

Go to: Ongoing Virtualization Operations and Maintenance

Dumping Install Logs

In order to dump install logs on a virtual UC installation, it is necessary to use a virtual serial port on the virtual machine. By default, a serial port is not present when deploying from the Cisco provided OVA. Thus it will often be the case that the first time you hit an installation problem and need to dump the logs, the serial port will not be available. Use this procedure to add a serial port to the virtual machine and dump the logs.


Follow this procedure to dump install logs to the serial port on the VM.

  1. When the VM is powered off, edit settings and add a serial port to the VM.
    Note Note: You cannot add one while the VM is running.
  2. You will be required at this time to attach the serial port to a file. Just attach to any temp/junk file, as this file will NOT be used to dump the logs.
  3. Power on the VM and start your installation. At boot up, linux will dump some garbage characters (escape sequence characters) into the temp file you attached to the serial port.
  4. When you're ready to actually dump the log files, attach a new, empty file to the serial port by editing settings of the VM while the machine is running. You do not have to power down the VM to change the file attached to the serial port.
  5. After the file is saved, you can open it using 7-zip (
  6. After you have a successful install in the VM, power off the VM, edit settings and remove the serial port from the VM.
    Note Note: Leaving the serial port (or any other unnecessary virtual hardware) can negatively impact performance of the VM. There is no other use of the serial port in a Unified CM VM other than dumping the install logs, so you will not need it again unless you do a fresh install.

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