KVM has KSM, so there is definitely the possibility of having say, 150x 1GB VMs on a 128GB physical RAM server; possibly much more than that depending how much

KVM has KSM, so there is definitely the possibility of having say, 150x 1GB VMs on a 128GB physical RAM server; possibly much more than that depending how much KVM/KSM has improved since I last looked at it.