A method and controller device for supplying battery power to a virtualized storage environment having a storage controller with a virtual machine manager and a second virtual machine. In response to a battery engaged event, the first virtual machine manager enables the image of the second virtual machine to be shared with a new instance of the second virtual machine so that the image does not have to be loaded therein. The first virtual machine manager then creates the new virtual machine. The old virtual machine shuts down non-necessary hardware devices and sets necessary hardware devices to low power mode. During this time, the new virtual machine executes a backup specific start-of-day (SOD) initialization sequence. The method also synchronizes the new and old virtual machines. The method also initiates a cache memory backup operation upon synchronization of the new and old virtual machines and then shuts down the old virtual machine.