An administrator notices that when a virtual machine is placed into a resource pool, a warning indicates that the virtual machine will receive a very large percentage of the total shares for memory.
Which action can be taken to resolve this problem?
A. Increase the memory resource allocation to the resource pool.
B. Increase the share value for the resource pool.
C. Change the shares setting from custom to high, medium, or low for the virtual machine.
D. Decrease the memory allocation for the virtual machine.
Correct Answer: C
Explanation/Reference:
Explanation:
Configuring resource shares helps an administrator to accomplish the following:
Performance Isolation - prevent virtual machines from monopolizing resources and guarantee predictable service rates.
Efficient Utilization - exploit undercommitted resources and overcommit with graceful degradation.
Easy Administration - control the relative importance of virtual machines, provide flexible dynamic partitioning, and meet absolute service-level agreements.
Shares specify the relative importance of a virtual machine (or resource pool). If a virtual machine has twice as many shares of a resource as another virtual machine, it is entitled to consume twice as much of that resource when these two virtual machines are competing for resources.
Shares are typically specified as High, Normal, or Low. For CPU shares these values equate to 2000 share for High, 1000 shares for Normal, and 500 chares for Low, with a 4:2:1 ratio, respectively. Thus configuring the database server’s CPU Shares to High while leaving the web server’s CPU Shares at Normal will ensure that the database server is entitled to twice the CPU resources than a web server.
Shares can also be set to a custom value, as is the probable case in this scenario.
Incorrect Answers:
A: The problem here is that the virtual machine in a resource pool is receiving a very large percentage of the total shares for memory. Increasing the resource pool’s memory resource allocation will not address this problem.
B: The problem here is that the virtual machine in a resource pool is receiving a very large percentage of the total shares for memory. Increasing the resource pool’s share value will not address this problem.
D: The virtual machine is in a resource pool. We therefore cannot decrease the memory allocation for the virtual machine.
References:
http://pubs.vmware.com/vsphere-55/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-55-resource-management-guide.pdf Page 12
Liebowitz, Matt, Christopher Kusek and Rynardt Spies, VMware vSphere Performance: Designing CPU, Memory, Storage, and Networking for Performance-Intensive Workloads, Sybex, Indianapolis, 2014, pp 87-88, 118