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

The following operations are supported:

• All types of backups, including backup copies

• Full restores

• Replication

Requirements for Managed Identities

If you use managed identitites to protect your Azure VMs, you must use a user-assigned managed identity (not a system-assigned managed identity), and the user-assigned managed identity must have the roles and permissions that are required by the Commvault software to protect the VMs.

For information about roles and permissions, see Configuring Access to Azure Resources.

The user-assigned managed identity is specifed in the VM provisioning settings for your Azure access node. For more information, see "Specify New VM Provisioning Settings" on the Specifying VM Provisioning Settings for Azure Access Nodes page.

Creation and Decommissioning of Access Nodes

Number of Access Nodes That Are Created for Backups

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

Number of Access Nodes That Are Created for Restores

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

• The number of VMs that are being restored

• The load on auto-scaled access nodes

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

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 on that access node after job completion, 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.