1. A computer-implemented method of deploying virtual machines, the method comprising: receiving a request to deploy a virtual machine residing on a source host computer to a plurality of target host computers having at least a first target host computer and a second target host computer, wherein the source host computer and the target host computers are connected to each other in a computer network over respective links, wherein a network connection between the source host computer and the first target host computer, without any intervening target host computers, defines a first link, and a network connection between the source host computer and the second target host computer, without any intervening target host computers, defines a second link, and wherein a network connection between the first target host computer and the second target host computer, without any intervening target host computers, defines a third link; determining deployment times over the links between the source host computer and each of the target host computers, and between each pair of the target host computers; determining a path through the computer network from the source host computer to the first target host computer and from the source host computer to the second target host computer, based on the determined deployment times; and deploying a first copy of the virtual machine at the first target host computer, and a second copy of the virtual machine at the second target host computer, based on the determined path, wherein the determined path through the computer network from the source host computer to the first target host computer includes the first link and no other links, and the determined path through the computer network from the source host computer to the second target host computer includes the first link, the third link, and no other links, and the first copy of the virtual machine is copied from the source host computer and the second copy of the virtual machine is copied from the first copy of the virtual machine at the first target host computer.