Memory Behavior when VM Limits are Set

There was a big buzz going around on Twitter this morning about memory management mechanisms implemented by the VMkernel in the event that a Guest OS has a limit set that is under its total assigned value.  The conversation was kicked off from Arnim Van Lieshout’s blog post on memory management.  This is NOT a good scenario to have in your ESX environment, and I have seen it many times due to lack of education on what setting a limit means, or simply having a bad template deployed throughout the environment.  I want to start by saying that I am not 100% sure this is exactly what the VMkernel does, but having seen it, troubleshot it, and written rules in enterprise virtualization monitoring products around the behavior, I have a pretty solid base of understanding.

URL: http://www.vmguru.com/index.php/articles-mainmenu-62/mgmt-and-monitoring-mainmenu-68/96-memory-behavior-when-vm-limits-are-set