Home » VMware » 2V0-621 v.2 » What action would correctly address the performance problems observed?
Refer to the Exhibit.
An administrator receives vRealize Operations alerts for the Health of the virtual machine PVMAPP_0 as shown in Exhibit 1:
The administrator clicks on the Analysis pane, as shown in Exhibit 2:
Based on the exhibits, what action would correctly address the performance problems observed?
A. Increase the number of vCPUs for PVMAPP_0.
B. Increase the allocation of memory for PVMAPP_0.
C. Increase the Memory limit for PVMAPP_0.
D. Increase the reservation in MHz for vCPUs for PVMAPP_0.
Correct Answer: A
Explanation/Reference:
Explanation:
The default Hardware Version of the vRealize Operations Manager virtual machine is 7, limiting the maximum vCPUs selection to 8. You can upgrade the Hardware Version of the Analytics machine to increase the vCPU limit.
Theoretically, the performance of PVM should be similar or better than HVM. But, this trend tends to break when the vCPU count increases from 20 vCPUS. This problem is counter intuitive and is only observed in case of vCPUs being greater than 20 physical cores. We classify this problem as sleepy lock anomaly, which occurs due to the usage of paravirtual interface in the ticket spinlock implementation that has been introduced to solve the Lock Holder Preemption problem without the architectural support (i.e. Pause Loop Exiting).
Take steps to analyze the scalability behavior of VMs with high core count (till 80 core). Our preliminary study suggests that besides cache contention bottleneck, the usage of ticket spinlock is another culprit for the degradation. We will take a step further and will try to analyze the scalability characteristics of these monster VMs by running other benchsuites from Mosbench.
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