📖 What is Azure Service Level Agreements (SLAs)?
Azure Service Level Agreements (SLAs) are formal contracts that define the guaranteed uptime and performance levels for specific Azure services. If the provider fails to meet these guarantees, the customer may be eligible for service credits based on the percentage of downtime.
"Remember that SLAs are calculated per service; combining multiple services can create a 'Composite SLA' which usually lowers the overall percentage."
📚 Certification: Microsoft Azure Fundamentals (AZ-900)
🔑 What are the Key Concepts of Azure Service Level Agreements (SLAs)?
- ▸ Uptime guarantees are expressed as percentages, such as 99.9%, defining the minimum expected availability of a service over a monthly billing period.
- ▸ Service credits are the primary remedy provided to customers when Azure fails to meet the guaranteed uptime specified in the formal SLA.
- ▸ Composite SLAs occur when multiple services are combined; the overall availability is calculated by multiplying the individual SLAs of each component.
- ▸ Availability Zones and redundancy strategies are used to increase the SLA percentage, as multi-instance deployments offer higher guarantees than single instances.
- ▸ Each Azure service has its own unique SLA, meaning the guarantee for a Virtual Machine differs from that of a Storage Account.
🎯 How does Azure Service Level Agreements (SLAs) appear on the AZ-900 Exam?
You may be asked to calculate the combined availability of a solution using two different Azure services, requiring you to multiply their individual SLA percentages.
A scenario might describe a service outage and ask what the customer is entitled to receive from Microsoft, focusing on the concept of service credits.
Expect questions where you must determine how to increase a service's SLA, such as moving from a single VM to a deployment across Availability Zones.
❓ Frequently Asked Questions
If a service has a 99.9% SLA, does Microsoft automatically refund money during an outage?
No, refunds are not automatic. Customers must typically submit a claim for service credits within a specific timeframe after the outage is documented and verified.
Why does adding more services to an architecture sometimes lower the overall SLA?
This is due to Composite SLAs. Since the system depends on all components working, multiplying percentages (e.g., 0.999 x 0.999) results in a lower total probability.