Hi, this somewhat sounds like beign affected by translation issues. So if I misunderstood you, please let me know and try try to clarify the misunderstanding.
> I found the windows vm that I boot with 2C16G40G Which number is that? Is this especially about very huge instances or was that meaning you see the effects no matter if you use 2G or 16G or 40G? > will allocate all memory in compute node, and it could only be set memory allocation manually with `virsh qemu-monitor-command <vm-id> --hmp "balloon 8192"` to change actual memory usage in compute node. Be careful about what you see. The balloon is likely doing exactly what it was told to. That will from the guest look like it would have allocated 8GB memory (preventing that other bits in the guest can grab it). But from the Host POV this memory isn't really allocated and can be used for something else. The WIndows OS (just like Linux) I'd expect to allocate from the remaining memory on demand, but again be aware that both will massively use caching - so over time all non-balloon-consumed memory can often be expected to be fully allocated by the guest. > In the meantime, the reduced memory in compute node will be increase in the > inner windows > system.. In contrast, The memory of Linux vm can be allocated automatically > by balloon, and > allocate actual memory by check top command in compute node. Again the balloon is meant to appear as if allocating/consuming memory from the guests POV. So that does not seem to be wrong unless I misunderstood you. > I think the windows vm should allocate memory automatically like Linux vm. It should already ... > And if I set memory manually, the reduced memory usage in compute node should > not transform > into the usage memory of inner windows system and reduce the available memory. If you set the balloon size you set the size of memory that is fake-consumed from the guests POV. That means: - if you increase the balloon size then less will be left usable from the guests POV. And since thereby it prevents the guest from really allocating that memory from the hosts POV the host can use it elsewhere - if you reduce the balloon size then at first no further allocation happens. All that happens is the balloon deflating which appears to the guest as if more memory now would be free. If the guest consumes this or not is depending on configuration and workload. > Is it a qemu bug or my incorrect configurations? Right now to me it feels more like a misconfig - or actually a conceptual misunderstanding or wrong exectations - than a bug. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1916313 Title: memory allocate issue of windows vm To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1916313/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
