Compared: The "Nines" of uptime, Azure Services SLA

Availability is basically the same as uptime. It’s often measured by “Nines”. Availability specified as a number of nines is often seen in marketing documents. The table below lists the downtime that the nines translate to -

Nines	Downtime
99%	Daily: 14m 24.0s Weekly: 1h 40m 48.0s Monthly: 7h 18m 17.5s Yearly: 3d 15h 39m 29.5s
99.9%	Daily: 1m 26.4s Weekly: 10m 4.8s Monthly: 43m 49.7s Yearly: 8h 45m 57.0s
99.95%	Daily: 43.2s Weekly: 5m 2.4s Monthly: 21m 54.9s  Yearly: 4h 22m 58.5s
99.99%	Daily: 8.6s Weekly: 1m 0.5s Monthly: 4m 23.0s Yearly: 52m 35.7s
99.999%	Daily: 0.9s Weekly: 6.0s Monthly: 26.3s Yearly: 5m 15.6s

Service Level Agreement (SLA) summary for Azure services (info as of September 2016; refer to the link for updates)

Azure Service	SLA
Azure DNS	valid DNS requests will receive a response from at least one Azure DNS name server at least 99.99% of the time
Traffic Manager	DNS queries will receive a valid response from at least one Azure Traffic Manager name server clusters at least 99.99% of the time
Storage	99.99% (99.9% for Cool Access Tier) of the time, Microsoft will successfully process requests to read data from Read Access-Geo Redundant Storage (RA-GRS) Accounts, provided that failed attempts to read data from the primary region are retried on the secondary region. At least 99.9% (99% for Cool Access Tier) of the time, Microsoft will successfully process requests to read and write data from Locally Redundant Storage (LRS), Zone Redundant Storage (ZRS), and Geo Redundant Storage (GRS) Accounts.
SQL Database - Basic, Standard, and Premium Tiers	at least 99.99% of the time customers will have connectivity between their single or elastic Basic, Standard, or Premium Microsoft Azure SQL Database and Microsoft's Internet gateway
SAP HANA on Azure Large Instances	For SAP HANA on Azure that have been configured in a High Availability Pair, Microsoft guarantees connectivity to at least one instance at least 99.99% of the time.
DocumentDB	at least 99.99% of the time Microsoft will successfully process requests to perform operations against DocumentDB Resources.
API Management Service instances running in the Premium tier	99.95%. API Management Service instances running in the Standard tier will respond to requests to perform operations at least 99.9% of the time.
App Service	99.95%. No SLA is provided for Apps under either the Free or Shared tiers.
Cloud Services & Virtual Machines that have two or more instances deployed in the same Availability Set	99.95%. For any Single Instance Virtual Machine using premium storage for all disks, we guarantee you will have Virtual Machine Connectivity of at least 99.9%.
ExpressRoute	99.95%
Function Apps running on App Service Plans	99.95%
VPN Gateway	99.95% availability for each Standard Gateway for VPN or Standard Gateway for ExpressRoute & High Performance Gateway for VPN or High Performance Gateway for ExpressRoute. 99.9% availability for each Basic Gateway for VPN or Basic Gateway for ExpressRoute.
Media Services	99.9% for Media Services Encoding, Streaming, Live Channels, Content Protection, Indexer
Mobile Engagement	99.9%
Mobile Services	99.9% availability of REST API calls to all provisioned Azure Mobile Services running in Standard and Premium tiers in a customer subscription. No SLA is provided for the Free tier of Mobile Services.
Multi-Factor Authentication	99.9%
Power BI Embedded	99.9%
Scheduler	99.9%
Search	99.9%
Security Center	99.9%
Service Bus	99.9%
SQL Data Warehouse	99.9%
SQL Stretch Database	99.9%
StorSimple	99.9%
Stream Analytics	99.9%
Visual Studio Team Services	99.9%
Azure Active Directory	99.9% availability of the Azure Active Directory Basic and Premium services, Azure Active Directory B2C service, Azure Active Directory Domain Services
Application Gateway	each Application Gateway Cloud Service having two or more medium or larger instances will be available at least 99.9% of the time.
Application Insights	data latency of the Application Insights Service will not exceed two hours 99.9% of the time.
Automation	99.9%
Azure Backup service	99.9%
BizTalk Services	99.9%
Cache	99.9%
Cognitive Services	Cognitive Services running in the Standard tier will be available at least 99.9% of the time
CDN	99.9%
Data Catalog	99.9%
Data Lake Analytics	99.9%
Data Lake Store	99.9%
Event Hubs	99.9%
HockeyApp	99.9%
HDInsight	99.9%
IoT Hub	99.9%
Key Vault	99.9%
Log Analytics	99.9%
Logic Apps	99.9%
Azure Monitor	99.9%
Site Recovery	99.9%

Azure Kubernetes Service (AKS), Virtual Machine Scale Sets, Service Fabric, Azure DevTest Labs are free services, therefore, they do not have a financially backed SLA.