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Oracle VM VirtualBox: Log files and how-to manage them.

Simon Coter
Senior Manager, Oracle Linux and Virtualization Product Management

One of the key tools you can use to diagnose any issues with VirtualBox is the VirtualBox log file for a vm session. VirtualBox always creates a log file which reflects the lifecycle of the virtual machine.

VirtualBox log files live in a per-user/per-vm standard directory that will be something like:

  • On Windows, this is "%HOMEDRIVE%%HOMEPATH%\\.VirtualBox\\Machines\\<vm name>\\Logs"; typically some- thing like "C:\\Users\\Username\\.VirtualBox\\Machines\\<vm name>\\Logs\\vbox.log"
  • On Mac OS X, this is "$HOME/VirtualBox/Machines/<vm name>/Logs"
  • On Unix-like systems (Linux, Solaris), this is "$HOME/.VirtualBox/Machines/<vm name>/Logs"

The log files are rotated such that the most recent is always called vbox.log and older ones are vbox.log.[123]. These log files contain lots of information about the capabilities of both the host and the guest vm and should be provided whenever reporting issues with VirtualBox. 

Log File Format 

The layout of the logfile varies based on whether you are resuming or starting initially but roughly follows this pattern:

Section Content Starts around
Header VirtualBox version, Host OS information and Host Hardware information Beginning of file
CFGM Dump A listing of the configuration information of guest (guest virtual hardware) \*\*\* CFGM dump \*\*\*
Host Information (CPUID dump) Low level CPU information of Host and what will be reflected to Guest \*\*\* CPUID dump \*\*\*
Creating the VM Information about the creation of the virtual machine environment \*\*\* End of CPUID dump \*\*\*
Powering on or Loading from saved state When powering on you'll see very little in the logs at this stage.  If loading from a saved state, information from the Saved State Manager about matching previous state to current environment. Changing the VM state from 'CREATED' to 'LOADING'
Resuming/Running Once the saved state is loaded, or the vm is booted, the guest code is executed. Changing the VM state from 'POWERING_ON' to 'RUNNING' or from 'LOADING' to 'RESUMING' or from 'SUSPENDED' to 'RESUMING'
Guest lifetime This part of the log contains entries concerning the lifetime of the Guest. Changing the VM state from 'RESUMING' to 'RUNNING'
Powering off or suspending A dump of the guest state at the time the vm was powered off. \*\*\* Guest state at power off \*\*\*
Statistics The statistics collected during the session are dumped out. \*\*\* Statistics \*\*\*

One important thing to consider, on VirtualBox logs, is the default timestamp format:

00:00:01.817 VRDP: TCP server listening on port 3389.

 

This is in the format HH:MM:SS.ms and is relative to the start of the vm. If you prefer to also have "wall clock time" you can set the environment variable before starting the vm:

  • Linux/Solaris/OS X 
export VBOX_RELEASE_LOG_FLAGS=time; VBoxManage startvm <vm-name>

 

  • Microsoft Windows 
set VBOX_RELEASE_LOG_FLAGS=time; VBoxManage.exe startvm <vm-name>

 

New Feature, part of the latest VirtualBox 5.1.

Starting from VirtualBox 5.1 release a further enhancement has been introduced while managing VirtualBox logs: VBoxBugReport.

Thanks to this utility you have the ability to collect all the logs into one unique output file; options available are:

  • Collect all the logs related to the VirtualBox installation (default)
  • Collect all the logs related to a specific Virtual Machine or to a group of Virtual Machines (VirtualBox installation included)
  • Collect all the logs related to all Virtual Machines registered (VirtualBox installation included)

 

Join the discussion

Comments ( 2 )
  • Cesar Murilo Sunday, January 26, 2020
    And how do I interpret errors in the log? What would be E1000?

    For example, there was an error in the initialization of my VM, the end of the log says:

    00: 00: 36.837881 ********************* End of statistics ********************* *
    00: 00: 36.838006 VUSB: Detached 'HidMouse' from port 1 on RootHub # 1
    00: 00: 36.890672 E1000 # 0: Interrupt attempts: 0
  • Simon Monday, January 27, 2020
    Hi Cesar,

    in case of issues those logs can be shared to our community on http://forum.virtualbox.org with the target to understand cause and possible solutions.
    Thanks

    Simon
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