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VMware ACE Administrator’s Manual
Starting a Virtual Machine Repeatedly in the Same State
You can configure the virtual machine to revert to the snapshot any time it is powered
off. To do so, choose VM > Settings > Options > Snapshot. Under When powering
off, select Revert to the snapshot. If you want the virtual machine to be suspended
when you launch it, suspend the virtual machine before taking the snapshot. Similarly,
if you want the virtual machine to be powered on or powered off when you launch it,
be sure it is powered on or powered off when you take the snapshot.
The Snapshot and the Virtual Machine’s Hard Disks
When a snapshot exists and the virtual machine saves data to disk, that data is written
to a set of redo-log files. These files have .REDO as part of the filename and are stored
in the virtual machine’s working directory.
Newly saved data continues to accumulate in the redo-log files until you take an
action that affects the snapshot.
• Remove the snapshot — When you remove the snapshot, the changes
accumulated in the redo-log files are written permanently to the base disks,
either the virtual disk files or the physical disks, depending on your virtual
machine’s hard disk configuration.
• Revert to the snapshot — When you revert to the snapshot, the contents of the
redo-log files are discarded. Any additional changes once again accumulate in
the redo-log files.
• Take a snapshot — If you take a snapshot when the virtual machine already has a
snapshot, changes stored in the redo-log files are written permanently to the
base disk. Then any subsequent changes once again accumulate in the redo-log
files.
The Snapshot and Other Activity in the Virtual Machine
When you take a snapshot, be aware of other activity going on in the virtual machine
and the likely impact of reverting to the snapshot. In general, it is best to take the
snapshot when no applications in the virtual machine are communicating with other
computers.
The potential for problems is greatest if the virtual machine is communicating with
another computer, especially in a production environment.
Consider a case in which you take a snapshot while the virtual machine is
downloading a file from a server on the network. After you take the snapshot, the
virtual machine continues downloading the file, communicating its progress to the