Improve the performance of highly used VMs using Azure Advisor

  • Article
  • 02/10/2025

Azure Advisor helps you improve the speed and responsiveness of your business-critical applications. You can get performance recommendations from the Performance tab on the Advisor dashboard.

  1. Sign in to the Azure portal.
  2. Search for and select Advisor from any page.
  3. On the Advisor dashboard, select the Performance tab.

Optimize virtual machine (VM) performance by right-sizing highly utilized instances

You can improve the quality of your workload and prevent many performance-related issues (that is, throttling, high latency) by regularly assessing your performance efficiency. The Azure Well-Architected Framework as the ability of your workload to adapt to changes in load. Performance efficiency is one of the five pillars of architectural excellence on Azure.

Unless by design, we recommend keeping your application's usage well below your virtual machine's size limits, so it can better operate and easily accommodate changes.

Advisor aggregates various metrics over a minimum of seven days, identifies virtual machines with consistent high utilization across those metrics, and finds better sizes (SKUs) for improved performance. Finally, Advisor examines capacity signals in Azure to frequently refresh the recommended SKUs, ensuring that they're available for deployment in the region.

Resize SKU recommendations

Advisor recommends resizing virtual machines when use is consistently high (above predefined thresholds) given the running virtual machine's size limits.

  • The recommendation algorithm evaluates CPU, Memory, VM Cached IOPS Consumed Percentage, and VM Uncached Bandwidth Consumed Percentage usage metrics.
  • The observation period is the past seven days from the day of the recommendation.
  • Metrics are sampled every 30 seconds, aggregated to 1 minute, and then further aggregated to 30 minutes (taking the average of 1-minute average values while aggregating to 30 minutes)
  • A SKU upgrade for virtual machines is decided given the following criteria:
    • For each metric, we create a new feature from the P50 (median) of its 30-mins averages aggregated over the observation period. Therefore, a virtual machine is identified as a candidate for a resize if:
      • Both CPU and Memory features are >= 90% of the current SKU's limits.
      • Otherwise, either
        • The VM Cached IOPS feature is >= to 95% of the current SKU's limits, and the current SKU's max local disk IOPS is >= to its network disk IOPS. or
        • the VM Uncached Bandwidth feature is >= 95% of the current SKU's limits, and the current SKU's max network disk throttle limits are >= to its local disk throttle units.
  • We ensure that:
    • The current workload utilization is better on the new SKUs because of higher limits and better performance guarantees.
    • The new SKU has the same Accelerated Networking and Premium Storage capabilities.
    • The new SKU is supported and ready for deployment in the same region as the running virtual machine.

In some cases, recommendations can't be adopted or might not be applicable, such as some of these common scenarios (there may be other cases):

  • The virtual machine is short-lived.
  • The current virtual machine is already provisioned to accommodate upcoming traffic.
  • Specific testing being done using the current SKU, even if not utilized efficiently.
  • There's a need to keep the virtual machine as-is.

In such cases, use the Dismiss/Postpone options associated with the recommendation.

We're constantly working on improving these recommendations. Feel free to share feedback on the Advisor forum.

For more information about Azure Advisor, see the following articles.

For more information about specific Advisor recommendations, see the following articles.