Paused Hyper-V VMs Do Not Release RAM
Monday, October 26, 2009
Pausing a VM is handy when you want to quickly and temporarily take a machine offline without shutting it down. For example, you may want to test cluster failover or you may need to briefly free up main processor resources.
Be aware, however, that pausing a VM does not free up the RAM associated with the VM. I've seen several customers make this mistake, thinking that they could essentially "over-subscribe" their Hyper-V host server by pausing running VMs to free up resources (RAM) and run other VMs.