With automatic scaling, you can configure the software to deploy access nodes in Azure regions only when they are needed, and then decommission the access nodes soon after you use them. The software uses power management (enabled by default) to power off access nodes after you stop using them. Automatic scaling, combined with power management, can reduce the cost of using access nodes in Azure to back up VMs.
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 software creates access nodes by cloning from the Commvault Azure image. The Commvault Azure image is deployed from the Azure Marketplace regions, so you always have the most recent version, you do not have to manually update the image, and the license agreement is automatically accepted.
You can use an additional setting to configure the autoscale access node to use a custom machine image instead of the Commvault machine image. In the additional setting Value, enter the location of the machine image file on your computer, for example C:\Documents\Images\package.ova. For the Azure autoscale setting, you can use the CVAutoScaleAzureImageForProxy additional setting. For more information on using additional settings, see Additional Settings.
You can configure automatic scaling only for hypervisors that use traditional authentication. However, if you have a hypervisor that uses managed identity authentication and you want to use it for automatic scaling, you can change the authentication method for the hypervisor to traditional.
Also, you can perform backup copy operations using automatic scaling.
Required Components
The following CommCell components are required for automatic scaling:
-
An Azure cloud access node
-
An empty server group where Azure access nodes are created and decommissioned
-
A network topology so that the access node and the server group can communicate
-
A hypervisor that you will enable to run automatic scaling
Access Node Limits
The software automatically scales out the number of access nodes based on the following characteristics:
-
The Recovery Point Objective (RPO)
-
The throughput rate
-
The Maximum number of access nodes setting in the Auto scale settings dialog box
Important
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. For more information, see Configuring a Hypervisor for Automatic Scaling.
Access Node Expiration
Automatically scaled access nodes shut down after they are idle for 30 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 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.