How regular conversion to VM works

The way the repeated conversions work depends on where you choose to create the virtual machine.

• If you choose to save the virtual machine as a set of files: each conversion re-creates the virtual machine from scratch.
• If you choose to create the virtual machine on a virtualization server: when converting an incremental or differential backup, the software updates the existing virtual machine instead of re-creating it. Such conversion is normally faster. It saves network traffic and CPU resource of the host that performs the conversion. If updating the virtual machine is not possible, the software re-creates it from scratch.

The following is a detailed description of both cases.

If you choose to save the virtual machine as a set of files

As a result of the first conversion, a new virtual machine will be created. Every subsequent conversion will re-create this machine from scratch. First, a new (temporary) virtual machine is created. If this operation succeeds, the old machine is replaced. If an error occurs during creation of the temporary machine, the temporary machine is deleted. This way, the conversion always ends up with a single machine. However, extra storage space is required during conversion to store the temporary machine.

If you choose to create the virtual machine on a virtualization server

The first conversion creates a new virtual machine. Any subsequent conversion works as follows:

• If there has been a full backup since the last conversion, the virtual machine is re-created from scratch. This involves creating a temporary virtual machine, as described earlier in this section.
• Otherwise, the existing virtual machine is updated to reflect changes since the last conversion. If updating is not possible (for example, if you deleted the intermediate snapshots, see below), the virtual machine is re-created from scratch.

Intermediate snapshots

To be able to update the virtual machine, the software stores a few intermediate snapshots of it. They are named Backup… and Replica… and should be kept. Unneeded snapshots are deleted automatically.

The latest Replica… snapshot corresponds to the result of the latest conversion. You can go to this snapshot if you want to return the machine to that state; for example, if you worked with the machine and now want to discard the changes made to it.

Other snapshots are for internal use by the software.