I have a server that is running Windows Hyper-V. Today I noticed that one of the images was consuming a large amount of memory on the server and choking off the other images. In the Hyper-V manager is shows an Assigned Memory of 30235 MB, and a Memory Demand of 45050 MB. But when I enter into the actual image and call up the task manager, it shows that only about 9 GB of memory is being used.

If the image isn't using the memory, why doesn't the Hypervisor return the memory back to the host so it can be available to other images? What can I do to make sure my other images don't choke?

The Guest operating system is Windows Server 2008 R2 Standard, service pack 1, BTW. Integration Services is installed on it and Dynamic Memory is configured in the guest server's settings. The 9 GB being used is what is shown in the Task Manager on the Guest Image (which also shows the 30+ GB available)

  • Are you using Dynamic Memory? Are you overcommitted on your host? How did you measure that only 9GB what used? What were you looking at there? Assuming you're using Dynamic Memory, what is the guest OS that's showing this behavior? – MDMarra Apr 17 '13 at 23:31
  • I will answer the questions as an edit on my question for ease of reading. – Peter Lange Apr 17 '13 at 23:38
  • Thanks for the edit. What Service Pack level is installed on the guest? – MDMarra Apr 17 '13 at 23:53
  • Its running Service Pack 1, and I was apparently incorrect about the version of Windows. Its Windows 2008 R2 Standard, Service Pack 1 (We have so many, I get mixed up sometimes.) – Peter Lange Apr 18 '13 at 0:39

To support Dynamic Memory on Windows Server 2008 Standard, you must be running at least Service Pack 2 and you must install hotfix KB2230887. The hotfix will add support for Dynamic Memory for the Standard and Web editions of Windows Server 2008. Not sure what Windows will do otherwise. As well, depending on the workload running on the virtual machine, it may be advisable to set a different dynamic memory cap than the default of 65535MB. SQL Server, Exchange Server, IIS with a large number of application pools and workers, will all eagerly consume a great deal of memory.

Also ensure that you have the latest Hyper-V integration installed, by using Hyper-V Manager to insert the integration services disk (under the Action menu) as seen here, then in the VM exploring the newly attached ISO image in the cd-rom drive and running the setup.exe.

Virtual Machine Connection showing the action menu with the insert integration services disk option

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.