"Unable to apply DRS resource settings on host" when running latency-sensitive VMs

Products

• VMware vCenter Server

Issue/Introduction

• The summary page of an ESXi host in vSphere Client shows a warning banner with the following message:

Unable to apply DRS resource settings on host. This can significantly reduce the effectiveness of DRS.

•  Same error can be found in system journal:

  <vcenter> vpxd[6768]: Event [162290084] [1-1] [YYYY-MM-DDTHH:MM:SS] [vim.event.DrsResourceConfigureFailedEvent] [error] [] [<cluster>] [162290084] [Unable to apply DRS resource settings on host <host_name> in <cluster>. A specified parameter was not correct: spec.memoryAllocation. This can significantly reduce the effectiveness of DRS.]

• vCenter Server - /var/log/vmware/vpxd/vpxd.log, has the following entry:

  [YYYY-MM-DDTHH:MM:SS] warning vpxd[11112] [Originator@6876 sub=MoResGroup opID=HB-host-xxxxx@4086-44584e9d] Receive ConfigIssue when processing RP updates from host [vim.HostSystem:host-xxxxx,<host_name>] type vmodl.fault.InvalidArgument on ManagedObject vim.ResourcePool:resgroup-3018 for method vim.ResourcePool.updateChildResourceConfiguration

• ESXi host - /var/run/log/hostd.log has the following entry:

  hostd.log: [YYYY-MM-DDTHH:MM:SS] warning hostd[2100325] [Originator@6876 sub=Vmsvc.vm:/vmfs/volumes/datastore/folder/vm_name.vmx opID=HB-SpecSync-host-xxxxx@2972391-11ec7f82-64-c13f user=vpxuser] Insufficient memory reservation for latency-sensitive VM. Expected memory reservation: 65536 MB, actual: 0 MB [YYYY-MM-DDTHH:MM:SS] warning hostd[2100325] [Originator@6876 sub=Hostsvc.ResourcePool ha-root-pool opID=HB-SpecSync-host-xxxxx@2972391-11ec7f82-64-c13f user=vpxuser] UpdateChildResourceConfiguration: N5Vmomi5Fault15InvalidArgument9ExceptionE(Fault cause: vmodl.fault.InvalidArgument

Environment

VMware vCenter Server 8.0.x
VMware vCenter Server 7.0.x

Cause

This issue occurs due to one or more powered on virtual machines on the host, which are configured for high-latency sensitivity without having a complete memory reservation set as well.

Resolution

To remove the warning message and to prevent it's reappearance, verify if the VM needs to be configured for high latency sensitivity, depending on which please apply one of the following changes:
 

Option A - reconfigure the VM for normal latency sensitivity

• In vSphere Client right-click on the virtual machine and select "Edit Settings"
• In the "Edit Settings" Interface, change into the tab "VM Options" and expand the "Advanced" section
• Look for "Latency Sensitivity" settings, click on the drop-down list to select "Normal" and save the change with [OK]:

 

Option B - configure a full memory reservation:

• In vSphere Client right-click on the virtual machine and select "Edit Settings"
• In the "Edit Settings" dialog, under "Virtual Hardware" tab, expand "Memory".
• Select the check box for "Reserve all guest memory (All locked)" as in the image below
• Save the change with [OK]
• To commit the change, either migrate the virtual machine to another ESXi host, or shutdown the virtual machine and power it back on.

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