Merge pull request #92681 from axisc/aschhab_premium_recommendations

adding recommendations on premium messaging units

Author: GitHubber17

articles/service-bus-messaging/service-bus-premium-messaging.md

@@ -66,6 +66,31 @@ The CPU and memory usage are tracked and displayed to the you for the following
 - Understand the capacity of resources purchased.
 - Capacity planning that helps you decide to scale up/down.
 
+## Messaging unit - How many are needed?
+
+When provisioning an Azure Service Bus Premium namespace, the number of messaging units allocated must be specified. These messaging units are dedicated resources that are allocated to the namespace.
+
+The number of messaging units allocated to the Service Bus Premium namespace can be **dynamically adjusted** to factor in the change (increase or decrease) in workloads.
+
+There are a number of factors to take into consideration when deciding the number of messaging units for your architecture:
+
+- Start with ***1 or 2 messaging units*** allocated to your namespace.
+- Study the CPU usage metrics within the [Resource usage metrics](service-bus-metrics-azure-monitor.md#resource-usage-metrics) for your namespace.
+    - If CPU usage is ***below 20%***, you might be able to ***scale down*** the number of messaging units allocated to your namespace.
+    - If CPU usage is ***above 70%***, your application will benefit from ***scaling up*** the number of messaging units allocated to your namespace.
+
+The process of scaling the resources allocated to a Service Bus namespaces can be automated by using [Azure Automation Runbooks](../automation/automation-quickstart-create-runbook.md).
+
+> [!NOTE]
+> **Scaling** of the resources allocated to the namespace can be either preemptive or reactive.
+>
+>  * **Preemptive**: If additional workload is expected (due to seasonality or trends), you can proceed to allocate more messaging units to the namespace before the workloads hit.
+>
+>  * **Reactive**: If additional workloads are identified by studying the resource usage metrics, then additional resources can be allocated to the namespace to incorporate increasing demand.
+>
+> The billing meters for Service Bus are hourly. In the case of scaling up, you only pay for the additional resources for the hours that these were used.
+>
+
 ## Get started with Premium Messaging
 
 Getting started with Premium Messaging is straightforward and the process is similar to that of Standard Messaging. Begin by [creating a namespace](service-bus-create-namespace-portal.md) in the [Azure portal](https://portal.azure.com). Make sure you select **Premium** under **Pricing tier**. Click **View full pricing details** to see more information about each tier.