Auto-Scaling for Azure Access Nodes

Auto-scaling, combined with power management, can reduce the cost of using Azure access nodes to back up VMs. With auto-scaling, the Commvault software deploys access nodes in Azure regions only when they are needed, and then uses power management (enabled by default) to power off and decommission the access nodes soon after you use them.

Supported Operations and Configurations

Support for auto-scaling of Azure VM access nodes is as follows:

  • All types of backups, including backup copies, are supported.

  • Azure hypervisors that use managed identity authentication are not supported. If you have a hypervisor that uses managed identity authentication and you want to use it for auto-scaling, change the hypervisor's authentication method to traditional.

Creation of Access Nodes

The Commvault software determines the number of access nodes to create for backups based on the following characteristics:

  • The Recovery Point Objective (RPO)

  • The throughput rate

  • The number of data readers that are configured for the VM group

  • The Maximum number of access nodes setting in the Auto scale settings dialog box


To increase the number of access nodes, change the Maximum number of access nodes setting instead of changing the number of data readers per access node.

Decommissioning of Access Nodes

Automatically scaled access nodes shut down after they are idle for 5 minutes. If an access node is shut down when a job request is initiated, then the access node is powered on and used. If no activity occurs for an additional 30 minutes on the access node that is shut down, then the access node is deleted from both the Command Center and the Azure portal.

If there are multiple access nodes in use during a backup operation, and some access nodes are backing up VMs, while other access nodes have completed backups for VMs (or are otherwise idle), the idle access nodes are shut down after 5 minutes.

If you manually remove an access node from the server group, it is not deleted from the Command Center or the Azure portal. You must add the access node back to the server group and allow the automatic process to delete the access node.

Log Files

To troubleshoot failed backup operations, you can view the log files for automatic scaling at the following location on the CommServe server: Commvault\ContentStore\iDataAgent\JobResults\CV_JobResults\AutoScale.