Update Redis with Zone Redundancy
This guide explains how to update your Azure Cache for Redis to enable zone redundancy for improved availability and resilience.
For Existing Premium Tier Redis Caches
Main advice: Please perform these changes out of hours, as there is a possibility of downtime.
If you already have a Premium tier Redis cache instance:
- Go to Access Package and request Redis Cache Contributor Access (Production). Once activated, proceed to the next step.
- Go to the Azure Portal
- Navigate to your Redis cache
- Go to Settings → Advanced settings in the left navigation menu
- Check the “Zone redundancy” option
- Click Save
Update Terraform Configuration
After zone redundancy has been enabled in the portal, the development team should update their Terraform configuration:
sku_name = "Premium"
family = "P"
rdb_backup_enabled = true
When you run terraform plan, it will show it needs to create a Storage Account but won’t recreate the Redis instance.
Running terraform apply will create the Storage Account needed for backup functionality.
Note: The Storage Account is required for the RDB backup feature enabled with
rdb_backup_enabled = truein your Terraform configuration.
Important Environment and Cost Considerations
Note: Zone redundancy should only be enabled for production environments to avoid higher costs in lower environments. This process is intended only for the following production subscriptions:
- DCD-CNP-Prod
- DTS-SHAREDSERVICES-PROD
Please ensure you are applying these changes only in the specified production subscriptions.