First published on MSDN on Apr 11, 2012
As I wrote my recent blog posts and did more research I found that is would be helpful to highlight the HealthCheckTimeout behavior ...
Updated Jan 15, 2019
Version 2.0
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Nice.
Hey Bob, can you provide some explanation about these two messages?
1) SQL Server Availability Group: [hadrag] Availability Group with resource ID '74be6b4d-be01-4559-bae9-3fa115d771ab' did not receive healthinformation before HealthCheckTimeout
2) SQL Server Availability Group: [hadrag] Failure detected, diagnostics heartbeat is lost
I found it on Cluster.log, and I know that it has relation with HealthCheckTimeout, because, after any of them, these messages are logged:
[RES] SQL Server Availability Group <AG1>: [hadrag] Availability Group is not healthy with given HealthCheckTimeout and FailureConditionLevel
The second was triggered when a doing some tests: I stopped worker thread running sp_server_diagnostics, expecting this would cause a timeout and trigger the first message... but, to my surprise, the second was triggered...
My question is: What the conditions happen with health worker that triggers each of these messages?