How Do I Clone Virtual Machines?

Virtual machines are sets of operating systems, software, and data that run in an isolated environment on top of another operating system. The advantage of this arrangement is that the user can simultaneously use two sets of otherwise incompatible software on the same computer. If a virtual machine has been extensively configured, it is sometimes desirable to make an exact copy, or clone. The exact method you should use to clone virtual machines depends on a variety of factors, such as the hardware and software used and whether or not the machine is currently deployed.

If you have newer hardware and an up-to-date operating system, chances are that your computer supports hardware virtualization. This feature allows the processor to handle requests from two different operating systems at the same time and keep the results separate in memory, essentially dividing available computing power and allowing virtual machines to run at full speed. For computers that do not support hardware virtualization, software emulation is used to imitate the same process, albeit with dramatic speed loss. Assuming that your virualization software supports both hardware vitualization and software emulation, it is possible to clone virtual machines between different hardware and operating systems, but cloning a virtual machine for use on a computer with poorer virtualization support will not have satisfactory results.

Once you are sure that the system to which you are planning clone virtual machines has better or equal virtualization support, the next step is checking the resources available. If the computer in question frequently uses all of its available RAM or 100% of its processor, it probably isn't a good candidate for a host. The machine can be reformatted and set up as a dedicated host for your virtual machine.

After an appropriate host is found or created, you can clone virtual machines. You must first take the machine offline. Cloning a deployed machine could result in damage to both the copy and the original.

Next, copy the entire operating folder of the virtual machine and any associated configuration files. To make a true clone, you must duplicate both the software running on the virtual machine and the configuration of the virtual hardware, including processor and memory allocation. If your virtualization software has a built in feature for collecting and copying these files, you should use it because automated scripts decrease the risk of data loss when you clone virtual machines.