86% RAM Used on Hyper-V Hypervisor that is only using 65% - Where is the missing 21%?

[Fazza]

Our monitoring system is saying that one of our Hyper-V Hypervisors is running at 86% RAM - the server has 256GB of RAM and around a dozen Virtual Machines on it so it should have plenty free, but it hasn't...

 

This is what task manager is showing:

 

 

This confirms that 86% of the RAM is indeed in use.

 

SCVMM says all the VMs are only using 133GB of RAM:

 

 

Resource Monitor says 61% of Physical Memory is being used:

 

 

 

If Hyper-V is only using 133GB of RAM, where is the 'missing' 123GB? Some will be used by the Hypervisor server itself, but task manager shows its fluctuating between 8GB and 12GB so theres 100GB allocated to something somewhere is is there a memory leak or something?

[Fazza]

After a bit or research, MonitoringHost.exe (which was using shed-loads of RAM) is used by SCOM and nothing else so in Resource Manager I ended the task and watched it slowly release all the RAM it was using and now the server is running as it should with loads of free RAM!

 

Just need to work out how to restart the SCOM client on the server now as we use that to monitor replication etc.