Guarantee Stream Analytics job reliability during service updates
Part of being a fully managed service is the capability to introduce new service functionality and improvements at a rapid pace. As a result, Stream Analytics can have a service update deploy on a weekly (or more frequent) basis. No matter how much testing is done there is still a risk that an existing, running job may break due to the introduction of a bug. If you are running mission critical jobs, these risks need to be avoided. You can reduce this risk by following Azure’s paired region model.
How do Azure paired regions address this concern?
Stream Analytics guarantees jobs in paired regions are updated in separate batches. As a result there is a sufficient time gap between the updates to identify potential issues and remediate them.
With the exception of Central India (whose paired region, South India, does not have Stream Analytics presence), the deployment of an update to Stream Analytics would not occur at the same time in a set of paired regions. Deployments in multiple regions in the same group may occur at the same time.
The article on availability and paired regions has the most up-to-date information on which regions are paired.
It is recommended to deploy identical jobs to both paired regions. You should then monitor these jobs to get notified when something unexpected happens. If one of these jobs ends up in a Failed state after a Stream Analytics service update, you can contact customer support to help identify the root cause. You should also fail over any downstream consumers to the healthy job output.