Vista - When are changes written to the .vhd file?

Hi all, I am trying to back up my .vhd file. However, do i need to shutdown
the virtual machine before i make a copy of the .vhd file in order to capture
the latest changes? Perhaps, let me illustrate my question below.

0900hrs: Start up virtual machine
0930hrs: Edit a text document in the machine. Save the file
0940hrs: Copy the .vhd file. // virtual machine still running.

Would the changes made in the text file be written to the .vhd file already?

Or the text file changes will only be updated after i shutdown the virtual
machine? I am curious because the timestamp of my .vhd file only reflects the
time it is started up. This leads me to think that .vhd file is only edited
when its started up, and hence what ever changes I make to any files while
the virtual machine is running is not immediately written to the .vhd file.

On Wed, 18 Feb 2009 23:11:01 -0800, anonymoussg
<anonymoussg@xxxxxx> wrote:
It depends on if you have undo disks enabled or not. With undo disks
you will not write anything to the VHD file until you shut down the
guest and reply yes to the question to commit your changes.

If you do not use undo disks then the VHD is in principle the storage
medium for the data, but inside the guest the actual write might be
delayed by Windows (if that is the guest operating system of course,
you did not specify and VPC is not limited to Windows guests...).
With a delayed write you never know when the actual data write
happens.

Also it is not advisable to copy the VHD file while the guest is
running because the copy operation might well lock the file which will
cause the guest to crash.
Since the VHD file is normally very big any copy operation will take a
very long time too...

--

Bo Berglund (Sweden)