An administrator removes a virtual machine from a resource pool and places it in the DRS root resource pool. Users report the performance of the application running on the virtual machine has improved. The virtual machine relocation was the only change that occurred.
What explains the change in application performance?
A. The memory, storage, and/or CPU settings of the original resource pool restricted access to resources for the virtual machine.
B. The configured memory, storage and/or CPU shares on the root resource pool are higher than the original resource pool.
C. The memory, storage and/or CPU settings on the root resource pool restricted access to resources for the virtual machine
D. The configured memory storage and/or CPU reservations on the root resource pool are higher than the original resource pool.
Correct Answer: A
Explanation/Reference:
Explanation:
A resource pool is a logical grouping of the resources (Memory, CPUs etc.) on an ESXi host or cluster. Resource pools can be grouped into hierarchies and used to hierarchically partition available CPU and memory resources.
Each standalone host and each DRS cluster has an (invisible) root resource pool that groups the resources of that host or cluster. Users can create child resource pools of the root resource pool or of any user-created child resource pool.
When configuring a resource pool, you can configure a “Reservation”. A reservation reserves a defined amount of CPU or memory resource to be used by the resource pool. The reserved resources cannot be used by VMs in another resource pool even if the resources are unused.
A resource pool’s ‘limit’ setting defines the upper limit for this resource pool’s CPU or memory allocation.
In this question, if the resource pool has limits defined, that could cause contention for resources within the resource pool. In this case, the VM may not be able to use all the resources (CPU, Memory etc.) that the VM has been configured to use.
By moving the VM to the root resource pool, the VM can use all available resources up to the limits defined in the VM settings.
Incorrect Answers:
B: You do not configure the memory, storage or CPU shares in the root resource pool. The root resource pool is invisible to users. All memory, storage and CPU resources in the cluster are automatically added to the root resource pool. Therefore, this answer is incorrect.
C: If the memory, storage and/or CPU settings on the root resource pool restricted access to resources for the VM, then moving the VM into the root resource pool would not have improved the performance. Therefore, this answer is incorrect.
D: You do not configure the memory, storage or CPU shares in the root resource pool. The root resource pool is invisible to users. All memory, storage and CPU resources in the cluster are automatically added to the root resource pool. Therefore, this answer is incorrect.
References:
https://pubs.vmware.com/vsphere-55/index.jsp#com.vmware.vsphere.resmgmt.doc/GUID-60077B40-66FF-4625-934A-641703ED7601.html