2V0-21.23 Question 40
Single answerA VMware administrator notices that virtual machines (VMs) in their environment experience performance degradation during peak workloads. The cluster is enabled with VMware Distributed Resource Scheduler (DRS) in fully automated mode. However, the administrator observes that VMs are not being migrated automatically to balance the load across hosts. What could be the reason for this behavior?
- A
DRS Automation Level for the cluster is set to 'Partially Automated'.
- B
VMware vSphere HA is disabled on the cluster.
- C
The cluster is running at full capacity and cannot accommodate live migrations.
- D
VM-to-Host affinity rules are preventing migrations.
Show answer and explanation
Correct answer: D
Explanation
VMware Distributed Resource Scheduler (DRS) in fully automated mode automatically balances workloads across hosts by migrating VMs when resource imbalances are detected. However, constraints like VM-to-Host affinity rules can override DRS's ability to move VMs, even in automated mode. This explains why the VMs are not being migrated despite performance degradation and the cluster's DRS configuration.
- A. Incorrect.
If the DRS Automation Level were set to 'Partially Automated', DRS would only make migration recommendations instead of automatically migrating VMs. However, the question explicitly states that the cluster is in 'fully automated mode', so this is incorrect.
- B. Incorrect.
vSphere HA (High Availability) is a different feature and does not impact the automatic load balancing functionality of DRS. Hence, this option is incorrect.
- C. Incorrect.
If the cluster were at full capacity, DRS would still attempt to balance workloads by migrating VMs to evenly distribute resource demands, provided there are no constraints. Hence, this is not the correct answer.
- D. Correct.
VM-to-Host affinity rules can restrict certain VMs from migrating to specific hosts or require them to run on particular hosts. If such rules are configured, DRS may not be able to migrate VMs to balance the load, even when in fully automated mode. This is the correct answer.