What are the opinions on allowing virtual memory inside a virtual machine?
For example, a host machine w/8 Gig of memory, I could run 4 VMs each w/2 Gig (roughly) and there would be no host swapping. However, in each VM I could have a 2Gig page file so the virtual server had 4Gig of usable memory, 2 physical 2 virtual.
OR... I could give each VM 4 Gig of "memory" and have the host use 8Gig of real memory and 8G of virtual memory and have no page file in each VM. Each VM would still have "4Gig" but the paging would occur on the host.
The warm-fuzzy part of me says setup paging in each guest like you would a real server and you're good. But the analytical side of me sees two major advantages to overcommitting the host memory and having no paging in the VM. First, the IO for the virtual memory is then handled by the host OS, which is closer to the bare metal, so it should be quicker. And second, paging would only be required if the host didn't have the memory available. If the guest wanted 4Gig, but other guests weren't using their memory then no paging would be required.