When building Azure cloud applications, it is very important to understand the specific features each service offers. It is also very important to know the scalability and performance targets for the different components in order to avoid throttling your apps.
Understanding Service Level Agreements (SLAs) is crucial to estimate how much downtime your application will pass through and be able to handle these transient faults.
For the best performance, collocate your application and storage in the same affinity group, and enable geo-replication for disaster recovery.
Note
For full Azure subscription and service limits, quotas, and constraints, you can check out the following document:
https://azure.microsoft.com/en-us/documentation/articles/azure-subscription-service-limits/
SLA for most Azure percentages can be found here: http://azure.microsoft.com/en-us/support/legal/sla/