VCP Quality Assurance & Improvement 4 — Questions and Answers
Question 1: What does the vSphere esxtop utility measure that helps diagnose storage performance issues?
- Network packet loss rates
- Disk latency (DAVG and KAVG) (Correct answer)
- CPU cache miss rates
- Memory page fault frequency
Correct answer: Disk latency (DAVG and KAVG)
esxtop's disk panel shows DAVG (device average latency) and KAVG (kernel average latency), which are critical for diagnosing storage bottlenecks.
Question 2: Which vSphere Network I/O Control (NIOC) feature ensures critical traffic types receive bandwidth during contention?
- Port group teaming policies
- Traffic shaping with burst size
- System traffic shares and reservations (Correct answer)
- VLAN tagging priority
Correct answer: System traffic shares and reservations
NIOC allows administrators to assign shares and reservations to system traffic types (vMotion, FT, storage) to prioritize critical network traffic.
Question 3: What log file should an administrator review to troubleshoot vCenter Server connection and inventory synchronization issues?
- /var/log/vmkernel.log
- /var/log/vpxa.log
- vpxd.log (Correct answer)
- /var/log/auth.log
Correct answer: vpxd.log
The vpxd.log file records vCenter Server daemon activity including inventory operations, connections, and task execution.
Question 4: An ESXi host shows a 'purple screen of death' (PSOD). What is the recommended first step for quality analysis?
- Immediately reboot the host to restore services
- Capture the vmkernel dump for VMware support analysis (Correct answer)
- Reinstall ESXi on the host
- Migrate all VMs to another host and decommission it
Correct answer: Capture the vmkernel dump for VMware support analysis
A PSOD generates a vmkernel core dump containing diagnostic information; capturing it is critical before rebooting so VMware support can analyze the root cause.
Question 5: Which vSphere feature continuously monitors cluster resource usage and proactively predicts capacity shortfalls?
- vSphere DRS
- vRealize Operations Manager (Correct answer)
- vSphere HA Admission Control
- vCenter Capacity Planning Plugin
Correct answer: vRealize Operations Manager
vRealize Operations Manager uses predictive analytics to forecast when cluster resources will be exhausted based on historical trends.
Question 6: What is the effect of setting a VM's CPU limit lower than its current CPU demand in vSphere?
- The VM will be migrated to a less loaded host by DRS
- The VM's CPU usage will be artificially capped, causing increased CPU Ready (Correct answer)
- The VM's memory will be reclaimed by the balloon driver
- vSphere HA will flag the VM as high priority
Correct answer: The VM's CPU usage will be artificially capped, causing increased CPU Ready
A CPU limit caps the VM's CPU consumption; when demand exceeds the limit, the VM accumulates CPU Ready time as it waits for scheduling.
Question 7: Which practice is recommended to ensure quality of vSphere snapshots used for backup and testing?
- Keep snapshots indefinitely to preserve state history
- Delete snapshots promptly after use to prevent delta disk growth and performance degradation (Correct answer)
- Take snapshots only during peak production hours
- Store all snapshots on the same datastore as the VM's base disk
Correct answer: Delete snapshots promptly after use to prevent delta disk growth and performance degradation
Snapshots create delta disks that grow over time and degrade VM performance; they should be deleted promptly after their purpose is fulfilled.
VCP Quality Assurance & Improvement 4
What does the vSphere esxtop utility measure that helps diagnose storage performance issues?