During peak operating hours, an administrator finds that a business-critical application running in a virtual machine is not performing as well as during normal hours.
Which memory management method can be used to guarantee that the application performs well at all times?
A. Set a reservation equal to the average memory utilization of the virtual machine running the application.
B. Set the share level to high for the virtual machine running the application and set the share level for all other virtual machines to low.
C. Check the Reserve all guest memory checkbox.
D. Set a reservation equal to the installed memory of the ESXi host running the application.
Correct Answer: C
Explanation/Reference:
http://www.vsysad.com/category/vmware-2/page/2/
There may be specific scenarios where it is not desirable to have a VM swap file. In my most recent experience a customer was short on storage so wanted to save space occupied by the large VM swap files, which are equal in size to the memory allocation to the VM. As physical memory on the ESXi host was not oversubscribed this would not have negatively impacted the performance of the VMs .
To remove the VM swap files perform the following steps:
1. In the vSphere client locate the VM, right-click on it and select Edit Settings.
2. Go to the Resources tab and select Memory
3. In the right-hand side check Reserve all guest memory (All locked) and click OK. The screenshot below shows this setting:
This setting reserves all 32GB of vRAM allocated to the VM on the ESXi host, and only if that memory is locked and guaranteed will that VM be able to power on.
Note: Removing the swap file is not recommended in solutions where memory has been over-subscribed to VMs. Doing so precludes the use of and benefits VMware memory management techniques such as ballooning, TPS (transparent page sharing), memory compression and host swapping (in that order).
