In a resource-constrained environment, which ESX Server memory conservation technique has the LEAST negative effect on the performance of a running virtual machine?

A.
Vmmemctl

B.
Using the .vswp file

C.
Transparent Page Sharing

D.
Lowering the Reservation variable

Explanation:

Balloon Driver – memory reclaimed from virtual machines by cooperation with the VMware Tools (vmmemctl driver) and guest operating systems. This is the preferred method for reclaiming memory from virtual machines, since it reclaims the memory that is considered least valuable by the guest operating system. The system “inflates” the balloon driver to increase memory pressure within the virtual machine, causing the guest operating system to invoke its own native memory management algorithms. When memory is tight, the guest operating system decides which particular pages of memory to reclaim, and if necessary, swaps them to its own virtual disk. This proprietary technique provides predictable performance that closely matches the behavior of a native system under similar memory constraints.