Always_Health

Question

Hi,

Is it necessary to always trun on AlwaysOn_Health event session in SQL Server 2016. If yes, does it impact on server performance?
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Answer 1

Hi @VijayKumar-4406,

Is it necessary to always trun on AlwaysOn_Health event session in SQL Server 2016. If yes, does it impact on server performance?

For Q1. Yes. It is necessary. If the session is not started, it cannot capture event data when an unexpected issue occurs.

For Q2. No, it will not impact the server’s performance.

Actually, after you create an availability group through the wizard in SQL Server Management Studio, this AlwaysOn_health session will be started. If you use T-SQL or Powershell scripts to create an availability group, the session will not start, you need to start it by manually.
The AlwaysOn_health session will generate a series of extended event log files named "AlwaysOn_health_<serial number>_<creation time>.xel" in the LOG directory of SQL Server. The event log file records some important events, such as changes in availability of replicas/databases, changes in Failover conditions, changes in synchronization between replicas, and so on. It also logs errors that occur in AlwaysOn itself, as well as any operating system issues or SQL Server database engine issues that may affect the health of the availability group.

More information: always-on-extended-events

BR,
Mia
If the reply helped, please “Accept Answer” and upvote it.--Mia

Answer 2

It is good to have always on it.
Also its an extended event which is having light weight impact on SQL Server performance.

Thanks,
Sreekanth Madambath