Not all will request memory from the free pool after initial startup.

Memory-usage behavior inside the VM depends on the applications. Externally-visible memory size will shrink, but only if Hyper-V decides that it has a need to shift the The balloon driver allocates memory inside the VM and releases it back to Hyper-V. Total visible memory size inside the VM will only grow, never shrink.

Dynamic Memory works for Debian guests of 2012 R2. 'Runtime Memory Resize' has nothing to do with Dynamic Memory so you can ignore that response. You might find more subject-matter experts on the I have not used Debian itself although I've used a number of Debian-based distribution and Dynamic Memory functions just fine for them. But Server 2012 R2 didn't support enabling the Microsoft third party UEFI CA but only the UEFIĬA that allows Windows guests to do secure boot, this only became possible with Server 2016. We do intend upgrading to 2019 in the foreseeable future, not only but also since Secure Boot will be supported in Debian 10 with a Microsoft-signed shim loader. Is this a known behaviour specific to Debian or Hyper-V with Server 2012 R2? The memory size never shrinks, even if the VM doesn't have any need for it.Worse even: If the startup memory becomes to low, the VM starts swapping instead of enabling the extra memory Hyper-V has granted the VM.At some point Hyper-V always show that the Linux VM has low memory, hence it will give more RAM to the Linux VM even if tools like free, top or htop show that the VM is perfectly happy with the memory it has and that Linux doesn't see the extra memory Hyper-V.A couple of seconds after bootup is finished, dmesg shows a message from hv_balloon how much the maximum RAM size is.I remember that Dynamic Memory was not supported with Linux in the earlier days but I decided that I might give it a go on Debian 9 (based on kernel 4.9) and the upcoming 10 (based on 4.19) on our Hyper-V hosts that are running 2012 R2.Īs of writing I don't think that the memory ballooning works as it should out of the box, and I couldn't others who have seen the following behaviour:

Hyperv ubuntu