How to make dedicated event hub cluster zone redundant?

Hello,

We have a dedicated self-serve scalable Event Hub cluster with 1 CU and want to enable zone redundancy for it and its Event Hub namespaces, but we're not sure how to achieve it.

Based on Azure docs, we found that there's a requirement for the cluster to have 3 CU's first and be deployed to a zone-redundancy supported region. Our cluster is in westeurope, which seems to support zone redundancy.

We tried the following ways to enable it:

1. Scale the current cluster to 3 CU through the Azure portal -> that didn't enable zone redundancy either for the cluster or for its namespaces
2. Create a new cluster using terraform's azurerm provider with 3 CU's (Dedicated_3 sku) -> the cluster was created, but it was still non zone redundant.
3. Create a new cluster through the Azure portal with 3 CU's -> the cluster was created, but still not zone redundant.

There were no flags or checkboxes anywhere to enable zone redundancy, neither in Azure portal nor in the Terraform provider and we're not sure what's missing. To be clear - we don't want geo replication, just zone redundancy enabled.

The way we were checking if the cluster or namespace is zone redundant already was by checking the resource's properties on Azure portal, which explicitly said "Zone Redundancy: Not Enabled" without hyperlinks or any buttons to change it.

We also confirmed it using Azure CLI commands like these:

az eventhubs namespace show  -g rg-name -n evhns-name  --query "{sku:sku.name, capacity:sku.capacity, zoneRedundant:zoneRedundant, clusterArmId:clusterArmId}" -o jsonc

and

az rest --method get --url "https://management.azure.com/subscriptions/sub_id/resourceGroups/rg-name/providers/Microsoft.EventHub/clusters/cluster-name?api-version=2026-01-01" --query "properties"

Both of them returned "zoneRedundant": false in their response.

Please let us know if you need any further details Any help would be appreciated.

Thanks.