Host Memory Usage is full in VM allotted

[agilan1620]

i install win 10 with virtio drivers iso and also installed qemu agent in windows 10, task manager shows memory usage in 14% but in vm summary page host memory usage is 100% (that means i alloted 16gb in full use), and also reflect in pve dashboard as i allotted 16gb is in use

i attached summary images in it, plz help me

 

[BobhWasatch]

First, please search the forum before posting. Somebody (always "new member") asks this question every few days.

First, if you have any PCIe devices passed in to the VM, then all VM memory must be pinned at startup to avoid issues with DMA. That's one thing. The other thing is that VM's that use memory for caching (i.e. most of them) will have memory that is "in use" from the hypervisor's view, but not from the VM's view.

The second PNG might be showing this. To the VM, cache is not "in use" because the OS in the VM can reclaim it at any time. There is no mechanism for the hypervisor to reclaim such memory though (other than the balloon driver) hence it is considered to be "in use".

 

[Impact]

Windows also tends to zero the memory under certain circumstances which causes it to be immediately allocated too. In general the RAM you give to a VM should be considered gone.