Virtual machine swap files
Every time a virtual machine is powered on, a swap file (.vswp) is created. Swap files are utilized by ESXi to swap memory in and out of the disk in case of contention. Swap files affect capacity due to the fact that they are the same size of the memory allocated to that virtual machine, minus any reservations configured.
Tip
The .vswp files are unique to ESXi and used only for hypervisor functions, that is, they are different from those memory techniques that are applied from within the guest OS, such as the swap partition for Linux and the page file for Windows.
As we know, the configuration maximums continue to grow in each and every new release of ESXi, with the current version allowing a rather substantial 1 TB of memory to be assigned to a single virtual machine. If we have deployed this amount of RAM to a VM (with no memory reservation), then we would also end up with a 1 TB swap file on our datastores. This extra swap file consumption is often overlooked during...
