Protecting your databases using Availability Groups adds an excellent tool to your disaster recovery and high availability capabilities. However, these capabilities bring with them the need to monitor the activities and functionality of the Availability Group. This session focuses on how to monitor your Availability Groups for both performance and general behaviour. Knowing what's going with your availability groups gives you better control over them because knowing is half the battle.

1. #sqlinthecityuk
Monitoring Availability Groups
Knowing Is Half the Battle
Grant Fritchey
Redgate Software
#sqlinthecityuk

2. #sqlinthecityuk
Get in touch
scarydba.com
grant@scarydba.com
@gfritchey
Grant Fritchey

3. #sqlinthecityuk
Knowing

4. #sqlinthecityuk
KnowingOther Stuff
THE BATTLE

5. #sqlinthecityuk
Knowing
Red Lasers
Blue Lasers
THE BATTLE

6. #sqlinthecityuk
Knowing
Kung Fu
Lasers
Deus Ex
Machina
THE BATTLE

7. #sqlinthecityuk
KnowingViolence
THE BATTLE

8. #sqlinthecityuk
Availability Groups
One or more databases in a failover group.
Failover can be to between one and eight
(2016) secondary servers.

9. #sqlinthecityuk
Knowing: AG, The Good
HA/DR Scenarios
Synchronous
Asynchronous
Readable secondaries
Ease of use
The cloud

10. #sqlinthecityuk
Windows Server Failover Cluster
Primary
Secondary Secondary
Readable
Listener

11. #sqlinthecityuk
Knowing: AG, The Bad
Network connectivity and throughput
Dual maintenance
Different servers, different plans
Synchronous replication
Monitoring

12. #sqlinthecityuk
Means of Gathering AG Knowledge
Dynamic Management Views
Performance Monitor
Extended Events
SQL Monitor

13. #sqlinthecityuk
Useful DMVs
Sys.dm_os_wait_stats
Sys.dm_hadr_availability_replica_states
sys.dm_hadr_database_replica_states
Sys.dm_exec_requests
Sys.dm_tcp_listener_states

14. #sqlinthecityuk
Necessary Perfmon Counters
SQL Server:Availability Replica
Bytes Sent to Replica/sec
Flow Control Time
Resent Messages/sec
SQL Server:Database Replica
Log Bytes Received/sec
Log Send Queue
Recovery Queue
Transaction Delay
Mirrored Write Transactions/Sec

15. #sqlinthecityuk
Interesting Extended Events
AlwaysOn_health Session
Hadr_database_flow_control_action
Debug

16. #sqlinthecityuk

17. #sqlinthecityuk
References
• Prerequisites, Restrictions, and Recommendations
for AlwaysOn Availability Groups
• SQL Server Customer Advisory Team
• Monitor Performance for AlwaysOn Availability
Groups
• Flow Control in AlwaysOn Availability Groups
• AlwaysOn Extended Events

18. #sqlinthecityuk
Knowing Is Half the Battle