Sun Microsystems VERSION 3.1.0_BETA2 user manual

1 First steps

current state of your VM is a variation based on the snapshot you took earlier. If you later take another snapshot, you will see that they will be displayed in sequence, and each subsequent snapshot is a derivation of the earlier one:

VirtualBox allows you to take an unlimited number of snapshots – the only limi- tation is the size of your disks. Keep in mind that each snapshot stores the state of the virtual machine and thus takes some disk space.

2.You can restore a snapshot by right-clicking on any snapshot you have taken in the list of snapshots. By restoring a snapshot, you go back (or forward) in time: the current state of the machine is lost, and the machine is restored to exactly the same state as it was when then snapshot was taken.5

Note: Restoring a snapshot will affect the virtual hard drives that are con- nected to your VM, as the entire state of the virtual hard drive will be reverted as well. This means also that all files that have been created since the snap- shot and all other file changes will be lost. In order to prevent such data loss while still making use of the snapshot feature, it is possible to add a second hard drive in “write-through” mode using the VBoxManage interface and use it to store your data. As write-through hard drives are not included in snap- shots, they remain unaltered when a machine is reverted. See chapter 5.4, Special image write modes, page 81 for details.

5Both the terminology and the functionality of restoring snapshots has changed with VirtualBox 3.1. Before that version, it was only possible to go back to the very last snapshot taken – not earlier ones, and the operation was called “Discard current state” instead of “Restore last snapshot”. The limitation has been lifted with version 3.1. It is now possible to restore any snapshot, going backward and forward in time.

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