fixed memery versus dynamic (balloon)

[mir]

Hi all,

What exactly is the difference between the old fixed memory allocation and the new using dynamic balloon allocated memory?
Any performance or what ever difference?

 

[dietmar]

What exactly is the difference between the old fixed memory allocation and the new using dynamic balloon allocated memory?

In short, when you run out of memory on the host, we steel memory from the guest and give it back to the host.

 

[mir]

In short, when you run out of memory on the host, we steel memory from the guest and give it back to the host.

To clarify:
The setting min means the lower barrier for memory of a client and if this barrier is met the host cannot steal any more memory from this client?
The setting max means the higher barrier for memory of a client where the host will not assign any more memory to this client?

 

[mo_]

furthermore if you have some KVM VM that could potentially require a ton of memory (i.e. windows) you can just outright give it... say 8GB and baloon it down to 4GB usable for the guest. What you accomplish by this is being able to give the VM the full 8GB of memory without having to reboot it if need be, just change the baloon size (assuming baloon drivers are installed)

 

[dietmar]

To clarify:
The setting min means the lower barrier for memory of a client and if this barrier is met the host cannot steal any more memory from this client?
The setting max means the higher barrier for memory of a client where the host will not assign any more memory to this client?

yes