Unable to set the eviction policy of our Azure Managed Redis cluster

Hello **Clif Day

**Azure Managed Redis (Enterprise) doesn’t let you change the eviction policy after the cache is created—eviction policies must be set at creation time. And if your cache is part of a geo-replication group (or you’re using RediSearch), eviction policies are also locked down post-creation. The only way to get a different policy is to spin up a brand-new cache with the desired maxmemory-policy.

https://learn.microsoft.com/en-us/azure/redis/quickstart-create-managed-redis#create-a-redis-instance

Why you couldn’t create in the same region is because most likely you’ve hit your per-region quota for Redis Enterprise caches.

Below instructions work without paying for support.

Please carefully follow my instructions below to create a new Service and subscription limits (quotas) request to allow access to deploy Azure SQL database in the desired region.

1. Navigate to this link to start the process:

https://portal.azure.com/#view/Microsoft_Azure_Support/HelpAndSupportBlade/~/overview

2. Click Create a support request button at top

3. If you see Support AI Assistant as shown below, click Switch to old experience button on right. Otherwise, proceed to step #4

4. Enter quota in the box and click Go

5. Select Others / Service and subscription limits (quotas) and click Next

6. Click Create a support request button, as shown

7. Select Issue type: Service and subscription limits (quotas), Subscription, Quota type: Azure Managed redis, click Next

8. Now you should be on Additional details tab. Click Enter details

9. Select Region access or Region access with zonal dependency, select Location you need, enter number of cores needed (you may need higher than screenshot), click Save and continue

10. Finish filling out Additional details tab, click Next, review and click Create. You should receive an automated email within a few minutes.

Once the quota’s raised, you’ll be able to deploy a new cluster with your chosen eviction policy.

Eviction policy on Azure Managed Redis cannot be changed after the instance is created. To use a different eviction policy, a new cache must be created with the desired configuration.

For Azure Managed Redis specifically:

• The clustering policy and certain behaviors (including eviction constraints for some modules like RediSearch) are fixed at creation time and cannot be modified later.
• To switch policies or behaviors that are creation-time only, the existing cache must be deleted and recreated with the new settings.

Regarding the region issue when creating a new cache:

• If a new cache cannot be created in the same region, this is typically due to regional capacity or quota constraints.
• In that case, either:
  • Resolve the regional limitation (for example, by working with support or adjusting quotas if applicable), then recreate the cache in the same region; or
  • Create the new cache in another region that has available capacity and adjust the application accordingly.

As a temporary workaround, increasing the cache size (as already done) is valid, but it does not allow changing the eviction policy. Long term, a new cache with the correct eviction policy is required.

References:

• Quickstart: Create an Azure Managed Redis Instance
• Scale an Azure Managed Redis instance
• Azure Managed Redis architecture
• New-AzRedisEnterpriseCache
• How to configure Azure Managed Redis
• Azure Cache for Redis retirement FAQ
• Scale an Azure Cache for Redis instance