What should you do?

You manage a cloud service that utilizes an Azure Service Bus queue. You need to ensure that messages that are never consumed are retained.

What should you do?
A . Check the MOVE TO THE DEAD-LETTER SUBQUEUE option for Expired Messages in the Azure Portal.
B . From the Azure Management Portal, create a new queue and name it Dead-Letter.
C . Execute the Set-AzureServiceBus PowerShell cmdlet.
D . Execute the New-AzureSchedulerStorageQueueJob PowerShell cmdlet.

View Answer

Answer: A

Explanation:

Deadlettering C From time to time a message may arrive in your queue that just can’t be processed. Each time the message is retrieved for processing the consumer throws an exception and cannot process the message. These are often referred to as poisonous messages and can happen for a variety of reasons, such as a corrupted payload, a message containing an unknown payload inadvertently delivered to a wrong queue, etc. When this happens, you do not want your system to come to grinding to a halt simply because one of the messages can’t be processed.

Ideally the message will be set aside to be reviewed later and processing can continue on to other messages in the queue. This process is called ‘Deadlettering’ a message and the Service Bus Brokered Messaging supports dead lettering by default. If a message fails to be processed and appears back on the queue ten times it will be placed into a dead letter queue. You can control the number of failures it takes for a message to be dead lettered by setting the MaxDeliveryCount property on the queue. When a message is deadlettered it is actually placed on a sub queue which can be accessed just like any other Service Bus queue. In the example used above the dead letter queue path would be samplequeue/$DeadLetterQueue. By default a message will be moved to the dead letter queue if it fails delivery more than 10 times.

Automatic dead lettering does not occur in the ReceiveAndDelete mode as the message has already been removed from the queue.

Explanation: https://www.simple-talk.com/cloud/cloud-data/an-introduction-to-windows-azure-service-bus-brokered-messaging/