Auto-Scaling for Amazon EC2 Access Nodes

With auto-scaling, the Commvault software deploys access nodes in AWS 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. Auto-scaling, combined with power management, can reduce the cost of using Amazon EC2 access nodes to back up VMs.

You can perform backup copy operations using auto-scaling.


Auto-scaling is supported only for Amazon EC2, Amazon EBS, and Amazon VPC backups. Auto-scaling is not currently supported for Amazon RDS, Redshift, DynamoDB, DocumentDB, EFS, FSx, or S3 backup.

Amazon Machine Images Used to Create Auto-Scaled Access Nodes

Commvault creates the auto-scaled access nodes by cloning an Amazon Machine Image (AMI). Commvault provides Windows and Linux AMIs.

Commvault-Provided AMIs

Commvault provides a version of the following AMIs for each platform release. To use these images, subscribe to them on the AWS Marketplace. The AMIs are deployed for each region that has instances that are backed up for the hypervisor.

Custom AMIs (MSP Environments Only)

If your environment has multiple AWS accounts, such as MSPs, you can specify a custom AMI. The following operating systems are supported for custom AMIs:

  • Linux:

    • CentOS Linux 8 or 7.4

    • Red Hat Enterprise Linux 8 or 7.4

    • Oracle Linux 8

  • Windows:

    • Microsoft Windows Server 2022 Editions

    • Microsoft Windows Server 2019 Editions

    • Microsoft Windows Server 2016 Editions

Amazon EC2 Instance Types

By default, an AWS Graviton (ARM 64-bit) image with the C6g.large instance type is used to create the auto-scaled access nodes. If an AWS Graviton (ARM 64-bit) image is not available in the region, then an X86 image with a C5.large instance is used.

You can specify a different instance type. The following AWS instance types are supported:

  • AWS Graviton (ARM 64-bit): c6g.large (default), c6g.xlarge, c6g.2xlarge, r6g.large, r6g.xlarge, r6g.2xlarge, r6g.4xlarge

  • X86: c5.large (default), c5.xlarge, c5.2xlarge, m5a.2xlarge, r5a.large, r5a.xlarge

Creation and Decommissioning of Access Nodes

Number of Access Nodes That Are Created

The number of access nodes that are required increases or decreases based on the amount of data you back up and the settings you configure for automatic scaling.

The Commvault software determines the number of access nodes to create 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 AWS 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. This can help reduce the compute cost.

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.