Performance problems in Azure VMs can stem from CPU, memory, disk, or network bottlenecks. Below are systematic steps to identify and resolve them.

1. Enable Diagnostics and Monitoring

  • Enable Boot Diagnostics: Capture screenshots and logs during startup.
  • Enable VM Insights / Azure Monitor: Collect metrics for CPU, memory, disk, and network.
  • Use PerfInsights Tool: Microsoft’s diagnostic utility that generates a report with bottlenecks and best practice recommendations.

Why: Diagnostics provide visibility into VM health and resource usage, helping pinpoint the root cause.

2. Check for CPU Bottlenecks

  • Azure Metrics: Look at Percentage CPU.
  • Inside VM: Use Task Manager or Performance Monitor (perfmon.msc) to check CPU utilization per process.
  • Resolution:
  • Scale up VM size (more vCPUs).
  • Optimize applications consuming high CPU.
  • Consider load balancing across multiple VMs.

3. Check for Memory Bottlenecks

  • Azure Metrics: Monitor memory usage (via VM Insights).
  • Inside VM: Use Resource Monitor (resmon) → Memory tab.
  • Resolution:
  • Increase VM size with more RAM.
  • Optimize applications with memory leaks.
  • Use paging file tuning if necessary.

4. Check for Disk Bottlenecks

  • Azure Metrics: Review Disk Read/Write Bytes/sec, IOPS, and Queue Depth.
  • Inside VM: Use Performance Monitor counters (Avg. Disk sec/Read, Avg. Disk sec/Write).
  • Resolution:
  • Upgrade to Premium SSDs for low latency.
  • Resize disk if capacity is insufficient.
  • Distribute workloads across multiple disks.

5. Check for Network Bottlenecks

  • Azure Metrics: Monitor Network In/Out Total.
  • Inside VM: Use netstat or Resource Monitor → Network tab.
  • Resolution:
  • Ensure VM size supports required bandwidth.
  • Use Accelerated Networking for high throughput.
  • Optimize application network usage.

6. Identify Application-Level Issues

  • PerfInsights Report: Highlights inefficient queries, memory leaks, or thread contention.
  • Windows Event Viewer: Check for application errors.
  • Resolution: Work with developers to optimize code or database queries.

7. General Remediation Steps

  • Right-size VM: Scale up/down based on workload.
  • Use Availability Sets/Scale Sets: Distribute load.
  • Patch OS and Applications: Ensure latest updates.
  • Review Azure Advisor Recommendations: Get optimization suggestions.

Best Practices

  • Always start with metrics collection before making changes.
  • Use alerts to proactively detect performance degradation.
  • Document findings for future troubleshooting.
  • Consider autoscaling for dynamic workloads.