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How to Calculate SLA for a Product

When we work against multiple Azure Services for a Single Product we need to handle the SLA (Service Level Agreement) carefully. It is not min or max or the average of SLA per services. Let’s take an example,

Table 1

Service

SLA

App Service

99.95%

Azure Active Directory

99.9%

   

 

What these % means,

%

Downtime/week

Downtime/month

Downtime/year

90%

16.8 hours

72 hours

36.5 days

99%

1.68 hours

7.2 hours

3.65 days

99.9%

10.1 minutes

43.2 minutes

8.76 hours

99.99%

1.01 minutes

4.32 minutes

52.56 minutes

99.999%

6.05 seconds

25.9 seconds

5.26 minutes

99.9999%

0.605 seconds

2.59 seconds

31.5 seconds

       

 

All the SLA of Azure is defines at https://azure.microsoft.com/en-us/support/legal/sla/

Based on Table 1 if an application uses both the Azure Services then the composite SLA of the Application would be

0.9995 x 0.999 = 0.9985005

Hence 99.85%. So it is neither 99.95% nor 99.9% it is altogether different.

Also one need to consider if there is anything in Application which defines its SLA.

Namoskar!!!