Why is remote desktop performance degrading although resource usage is normal?

Question

During the past week, we've noticed a significant degradation of the performance on one of your Azure VM's. There are no related errors reported and resource monitor shows utilization is normal. We've specifically noticed the vm taking longer than normal to load the desktop, lag in opening applications and windows explorer.

While researching the issue I found that there was a resource health report that said, "This virtual machine was paused for 0.699000 seconds due to a memory preserving Live Migration operation. No additional action is required from you at this time." This was about the time that the degradation started. The server is our primary server for a number of business processes and I need this resolved ASAP.

Answer 1

@Kevin Nelson

A VM pause of ~0.7 seconds due to a memory-preserving Live Migration is normal Azure behavior. Microsoft routinely performs Live Migration during platform maintenance, causing a very brief pause (typically under one second) while preserving memory, disk, and network connections.

This is not expected to cause ongoing or long-term performance issues and is intended to improve stability by moving VMs away from unhealthy hosts. If slowness continues after the pause, Live Migration is not the cause. In such cases, Microsoft recommends treating it as a general VM performance issue by reviewing Azure VM metrics especially disk performance, as disk throttling or low IOPS commonly cause slow logins and File Explorer lag even when CPU appears normal.

Running PerfInsights from the Azure Portal is the primary diagnostic step. If no in-guest issues are found, redeploying the VM is supported to move it to new host hardware; if the issue persists, open a Microsoft Support ticket with the PerfInsights report and Azure metrics.

1. Maintenance for virtual machines in Azure - https://learn.microsoft.com/en-us/azure/virtual-machines/maintenance-and-updates
2. Understand VM reboots - maintenance vs. downtime - https://docs.azure.cn/en-us/virtual-machines/understand-vm-reboots
3. Troubleshoot Azure virtual machine performance on Linux or Windows - https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/linux/troubleshoot-performance-virtual-machine-linux-windows
4. Virtual machine and disk performance - https://learn.microsoft.com/en-us/azure/virtual-machines/disks-performance
5. Run Performance Diagnostics reports on Azure virtual machines - https://learn.microsoft.com/en-us/azure/azure-monitor/vm/performance-diagnostics-run?tabs=windows
6. Use Performance Diagnostics in Azure Monitor to troubleshoot VM performance issues - https://learn.microsoft.com/en-us/azure/azure-monitor/vm/performance-diagnostics?tabs=windows

Answer 2

While your initial response wasn't actually the answer, as there was no useful findings in the perfinsight. Your comment response following that was the correct option. I redeployed and reapplied the vm to a new host and it's working as expected now.