SQL Server relies on Windows Server Failover Clustering for high availability, which allows a group of computers and storage devices to work together as a single system. It uses failure detection to automatically fail over services to another node if one fails. SQL Server provides two high availability solutions - a failover clustered instance which uses shared storage, and Always On availability groups which replicate data between nodes without shared storage and allow read-only access on secondary replicas.

1. SQL Server
HOW HIGH AVAILABILITY WORKS IN

2. WHY USE
TRUCKS

3. SQL Server
RELIES ON ANOTHER PLATFORM FOR
HIGH AVAILABILITY

4. WINDOWS SERVER
FAILOVER CLUSTER
a GROUP OF COMPUTERS and storage devices
WORKING TOGETHER that you can access as a
SINGLE SYSTEM
“

5. stop service

6. wait service
stop service

7. start service
wait service
stop service

8. WINDOWS SERVER
FAILOVER CLUSTER
HEALTH DETECTION

9. FAILURE DETECTION
WINDOWS SERVER
FAILOVER CLUSTER

10. AUTOMATIC FAILOVER
WINDOWS SERVER
FAILOVER CLUSTER

11. SQL Server
HIGH AVAILABILITY SOLUTIONS

12. SQL Server
FAILOVER CLUSTERED INSTANCE
SHARED STORAGE

13. SQL Server
Application
2-NODECLUSTER
traditional
Windows Server Failover Cluster

14. SQL Server
SHARED NOTHING
ALWAYS ON AVAILABILITY GROUPS

15. Application
SQL Server
log data
Windows Server Failover Cluster
Primary Replica
SQL Server
log data
Secondary Replica
Commit
SQL Server
log data
Secondary Replica

16. ACTIVE
ONLY ONE NODE CAN BE THE
PRIMARY
MASTER
IN BOTH
CASES

17. …if one or more cluster nodes will
fight for ownership of resources

18. ACCESSED THRU A COMBINATION OF
VIRTUAL NETWORK NAME
VIRTUAL IP ADDRESS
+

19. WINDOWS SERVER
FAILOVER CLUSTER

20. SQL Server
HOW HIGH AVAILABILITY WORKS IN