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How to do capacity planning for Azure Event Hubs on Azure Stack Hub

As an operator, you manage your Azure Stack Hub capacity by setting quotas on resources. You control Event Hubs resource consumption by setting quotas on the maximum number of cores that Event Hubs clusters can use. Users create Event Hubs clusters when they deploy an Event Hubs resource. This article also covers various resource consumption requirements for the resource provider.

Cluster resource consumption

Users create Event Hubs clusters based on Capacity Units (CUs). They don't specify a CPU core count when creating an Event Hubs cluster. However, every CU directly maps to a specific number of cores consumed.

Your users need to create Event Hubs clusters with CUs that meet their business requirements. To set quota configuration, review the following table for:

  • The total cores used by a 1 CU Event Hubs cluster.
  • The approximate capacity required for consumption of other resources, including VM storage, memory, and storage accounts.
VM type Cluster nodes Cores per VM/node Total cores VM storage Memory Storage accounts Public IPs
1 CU Event Hubs cluster D11_V2 5 2 10 500 GiB 70 GiB 4 1

All Event Hubs clusters use a D11_V2 VM type for their nodes. A D11_V2 VM type consists of 2 cores. So 1 CU Event Hubs cluster uses 5 D11_V2 VMs, which translates into 10 cores used. When you determine the number of cores to configure for a quota, use a multiple of the total cores used by 1 CU. This calculation reflects the maximum CU count you allow your users to use when creating Event Hubs clusters. For example, to configure a quota that allows users to create a cluster with 2 CUs of capacity, set your quota at 20 cores.

Important

For production deployments that require high availability (HA), use a two CU cluster. For non-HA deployments and development or test environments, use one CU.

You can scale out CU units from smaller to larger through the Create Event Hubs Cluster blade. Scale in (from larger to smaller) isn't supported.

Resource provider resource consumption

The Event Hubs resource provider consumes a constant amount of resources, regardless of the number or sizes of clusters that users create. The following table shows the core utilization by the Event Hubs resource provider on Azure Stack Hub, and the approximate resource consumption by other resources. The Event Hubs resource provider uses a D2_V2 VM type for its deployment.

VM Type Cluster Nodes Cores VM Storage Memory Storage Accounts Public IPs
Event Hubs resource provider D2_V2 3 6 300 GiB 21 GiB 2 1

Important

Quotas don't control resource provider consumption. You don't need to include the cores that the resource provider uses in your quota configurations. Use an administrator subscription to install resource providers. The subscription doesn't impose resource consumption limits on operators when they install their required resource providers.

Total resource consumption

The total capacity that the Event Hubs service consumes includes resource consumption by the resource provider, and consumption by user-created clusters.

The following table shows the total Event Hubs consumption under various configurations, regardless of whether they're managed by quota. These numbers are based on the resource provider and Event Hubs cluster consumptions that the previous section presented. You can easily calculate your total Azure Stack Hub usage for other deployment sizes by using these examples.

Cores VM Storage Memory Storage Accounts Total Storage* Public IPs**
1-CU cluster + resource provider 16 800 GiB 91 GiB 6 variable 2
2-CU cluster + resource provider 26 1.3 TB 161 GiB 10 variable 2
4-CU cluster + resource provider 46 2.3 TB 301 GiB 18 variable 2

* The ingress data block (message or event) rate and message retention are two important factors that contribute to the storage used by Event Hubs clusters. For example, if message retention is set to seven days when creating an event hub, and messages are ingested at a rate of 1 MB/s, the approximate storage used is 604 GB (1 MB x 60 seconds x 60 minutes x 24 hours x 7 days). If messages are sent at a rate of 20 MB/s with a seven days retention, the approximate storage consumption is 12 TB. Be sure to consider ingress data rate and retention time to fully understand storage capacity consumption.

** You consume public IP addresses from the network quota provided as part of your subscription.

Next steps

Before you begin the installation process, complete the Prerequisites for installing Event Hubs on Azure Stack Hub.