This question requires that you evaluate the underlined text to determine if it is correct.

This question requires that you evaluate the underlined text to determine if it is correct.

You have an application that is comprised of an Azure web app that has a Service Level Agreement (SLA) of 99.95 percent and an Azure SQL database that has an SLA of 99.99 percent.

The composite SLA for the application is the product of both SLAs, which equals 99.94 percent.

Instructions: Review the underlined text. If it makes the statement correct, select “No change is needed”. If the statement is incorrect, select the answer choice that makes the statement correct.
A . No change is needed
B . the lowest SLA associated to the application, which is 99.95 percent
C . the highest SLA associated to the application, which is 99.99 percent
D . the difference between the two SLAs, which is 0.05 percent

View Answer

Answer: A

Explanation:

Composite SLAs involve multiple services supporting an application, each with differing levels of availability. For example, consider an App Service web app that writes to Azure SQL Database.

At the time of this writing, these Azure services have the following SLAs:

– App Service web apps = 99.95%

– SQL Database = 99.99%

What is the maximum downtime you would expect for this application? If either service fails, the whole application fails. The probability of each service failing is independent, so the composite SLA for this application is 99.95% × 99.99% = 99.94%. That’s lower than the individual SLAs, which isn’t surprising because an application that relies on multiple services has more potential failure points.

References: https://docs.microsoft.com/en-us/azure/architecture/reliability/requirements#understand-service-level­agreements