In other words what is the purpose of Limiting ?
An example: Consider your boss wants to have a VM for his own use with 16GB memory. You assign 16GB memory to it (this is what the guest OS will see) but limit memory to 2GB (because you know he won't need 16GB anyway) Image may be NSFW.
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Seriously, I don't see a real use case for memory limits. What I could think of is an environment, where users are charged for physical memory usage, but need an option to dynamically increase it without downtime for the VM (i.e. the VM does not support hot-adding memory).
André
