1. A method of installing a software patch in a system, comprising: operating a first controller virtual machine on a network server; determining whether a new software patch for the first controller virtual machine is available; responsive to determining that the new software patch for the first controller virtual machine is available, replicating the first controller virtual machine with the new software patch into a replica controller virtual machine in the system; enabling the replica controller virtual machine; synchronizing the first controller virtual machine with the replica controller virtual machine; copying memory and system state data from the first controller virtual machine to the replica controller virtual machine; responsive to copying memory and system state, copying a bitmap of on-going transactions from the first controller virtual machine to the replica controller virtual machine; and operating the replica controller virtual machine without suspending the first controller virtual machine.