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Arvo Bowen
Asked: 2016-08-04 05:04:17 +0800 CST

Guest VM showing HIGH memory usage when nothing is using the memory

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I have a guest VM setup in my Hyper-V environment that I'm trying to us dynamic memory with. The following settings are being used...

  • Startup RAM: 8192
  • Minimum RAM: 2048
  • Maximum RAM: 8192
  • Memory buffer: 20%
  • Memory weight: Medium on the slider

enter image description here

I think I might have something configured wrong because as soon as I boot up the VM and go into task manager on the guest VM to look at the performance tab I see that the server has the following usage... enter image description here

The funny part is that NOTHING is using that memory (below sorted with highest mem at top)... enter image description here

Why does it show such a high memory usage?

UPDATE

Per an answer provided I wanted to show the resource manager too. It shows the exact same thing. enter image description here

memory hyper-v memory-usage hyper-v-server-2012-r2

3 Answers

  1. You enabled Dynamic Memory. So, while there's nothing requiring that memory in your VM, the hypervisor asked for the memory back, and received it. To make sure that this memory that the guest OS has released back to the hypervisor isn't accidentally used (which would cause the guest OS to fault,) the Dynamic Memory integration component (a device driver) in the guest has allocated it. This is why the report shows the memory as allocated.

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  2. Hyper V is bare metal - meaning that it won't show up in task manager. Try using the resource manager instead - you'll get more details.

    See Why does the Task Manager does not show any activity from Hyper-V?

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  3. This is not a Hyper-V issue, but a SQL Server one. It's fairly common for SQL Server to suck up all the available memory in the system (if its maximum memory usage is not limited), but for this to not be reported by Task Manager, as discussed here.

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