An ever-growing number of virtual machines (VMs) on a server that lowers its efficiency. Machine underutilization is one of the reasons for virtualizing servers in the first place; however, instances of virtual machines can be dynamically allocated to servers, and if too many VMs are added without proper management, they can overwhelm the hardware and decrease efficiency. In addition, too many VMs can also swamp the network. See
server sprawl and
virtual machine.