VMware Workstation 5.0

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What Is Captured by a Snapshot?

A snapshot captures the entire state of the virtual machine at the time you take the snapshot. This includes:

  • Memory state — The contents of the virtual machine's memory
  • Settings state — The virtual machine settings
  • Disk state — The state of all the virtual machine's virtual disks
  • Snapshots operate on individual virtual machines. In a team of virtual machines, taking a snapshot preserves only the active virtual machine's state. See The Active Virtual Machine.

    When you revert to a snapshot, you return the virtual machine's memory, settings, and virtual disks, to the state they were in when you took the snapshot. If you want the virtual machine to be suspended, powered on, or powered off when you launch it, be sure it is in the desired state when you take the snapshot.

    Note: The state of a physical disk or independent disk is not preserved when you take a snapshot.

    Snapshots 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 that snapshot. In general, it is best to take a 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 server. If you revert to the snapshot, communications between the virtual machine and the server are confused and the file transfer fails.

    Or consider a case in which you take a snapshot while an application in the virtual machine is sending a transaction to a database on a separate machine. If you revert to that snapshot — especially if you revert after the transaction starts but before it has been committed — the database is likely to be confused.

    See Snapshot Actions as Background Activity.

    Excluding Disks from Snapshots

    In certain configurations, you may want to have some disks revert to a snapshot while other disks retain all changes. You can exclude virtual disks from a snapshot by changing the disk mode.

    For example, you may want a snapshot to preserve a disk with your operating system and applications, while always keeping the changes to a disk with your documents. For the procedure, see Changing Disk Mode to Exclude Virtual Disks from Snapshots.

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