Virt Manager configuration:

enter image description here

Guest memory usage right after booting (nothing is running): enter image description here

I'm running virt-manager on a standard Ubuntu 17.10 system. In Proxmox, the same general configuration (with ballooning enabled) would allocate 8GB of the host but the guest would have roughly 1-2GB used out of 16GB instead of this.

I'm pretty sure I have all the guest drivers installed. (qemu guest, virtio stuff, balloon driver & service)

This is not my first QEMU VM, but the only one outside of Proxmox (which I'm assuming does some extra stuff that virt-manager doesn't).

What really exacerbates this issue is if I set the Current allocation to 2GB, the guest has about 15.6GB compressed and most software won't launch or run correctly because there's no free system memory...


:~$ free -m
              total        used        free      shared  buff/cache   available
Mem:          32163       20273        8949         176        2940       11325
Swap:          2047           2        2045

enter image description here

Hardly anything is running on the host. It looks like the entire 16GB is getting claimed but simultaneously most of that memory is inaccessible to the guest.

  • 1
    Could you please post free -m output from the guest and also the guest XML deffinition file (virtual HW...). Jan 6, 2018 at 13:24
  • Not sure where the configuration is saved. Guest is Windows 10 so free -m isn't recognized. Appended host's free -m.
    – Enigma
    Jan 7, 2018 at 4:35
  • What do you mean by "compressed"? That word doesn't make sense in the context you've used it. Apr 15, 2018 at 19:27
  • @Jaroslav Kucera: This is a Windows guest, free -m is a Linux command, am I missing something? You wrote to run it in the guest?
    – MrCalvin
    Aug 9, 2019 at 8:25
  • Re-read the first 2 comments here which should clarify what happened and why. I've since transferred this windows VM guest to bare metal and no longer have this issue.
    – Enigma
    Aug 26, 2019 at 22:23

1 Answer 1


usual and expected behaviour. qemu/kvm allocates the max ram until balloon service is started. afterwards any ram consumed by balloon service is free (from host pov)

  • Yes, but there are committed 10GB! One(me at least) would expect this to be 1-2GB. But when you set max higher than current you get this strange behaviour. Looking for an answer on another [thread] (unix.stackexchange.com/questions/534679/…)
    – MrCalvin
    Aug 9, 2019 at 8:23
  • ...and I mean those 10GB will stay like that, it's not just right after boot (at least that's what I see on my system).
    – MrCalvin
    Aug 9, 2019 at 8:28

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