Let's take a look at what Azure Lazar,
a service level agreement, or LA, is a formal document that specifies the Microsoft commitment to operate. The service
defines the performance standards like, for example, up time or connectivity guarantees that apply to that service
and outlines what happens if the service doesn't meet the specified standards.
Every product or service on Azure has their own LA.
What that means is that virtual machines may have a different S l A. Than as your storage, which might have a different S l. A. Than an SQL database.
There are also some special requirements regarding how the product should be used and configured in order to meet the L. A.
It is important to read the L A for each service that you plan to use, so you can understand what the impact will be on your application.
Very often, the performance target free services are expressed in the forms of up time and latency.
A typical example is Azure Cosmos DB, with 99.999% up time and 10 milliseconds. Latency on DB read and write operations.
You'll hear that a lot for a particular services. Three nines or five nines.
What those refer to is the up time of the service, expressed as a percent.
Three nines is 99.9% while 59 is 99.999%.
Here's a table that you can use to compare the up time expressed in percent to the down time, during which the service is not accessible, expressed in hours.
As you can see, there is a huge difference between the 99% up time and five nines uptime.
In the first case, the services inaccessible or down for more than seven hours per month,
while in the latter it's only inaccessible for 26 seconds.
Coming back to our example with Azure Cosmos db,
you should expect that services accessible practically all the time.
If that is not the case, you can complain to Microsoft and request a service credit.
If Microsoft is not able to keep the performance target for an azure service, they commit to compensating you for that.
This compensation can be in the form of a credit to your monthly bill for that particular service.
The following table shows the credit that you may be able to receive. If this service doesn't perform, according to the LA
Looking at the first row. What the table shows is that if the service up time is less than 99.9% or three nines, you will receive 10% credit towards your bill.
Looking back to the previous table. If the service is inaccessible for more than 43 minutes and 50 seconds per month,
you can receive 10% credit towards your bill for this service.
Keep in mind that the credit is only towards the cost of the underperforming service.
If you, for example, use virtual machines and as your storage and the virtual machines are not performing, according to the L. A. But as your storage is,
you will only receive a credit for the virtual machines charge.
You'll still need to pay the full bill for your storage consumption.
To actually request a credit,
you'll need to submit a service request to the Azure support team,
and we'll see how to do that in one of the next videos