In all SQL server failover clusters in our environment, It came to our notice that the SQL Server Agent is spamming the Application eventlogs under event viewer below entries every second in the Active node.[sqagtres] LooksAlive request. [sqagtres] CheckServiceAlive: returning TRUE (success)
It was observed that this incident started to occur after the scheduled windows patching.
Microsoft had identified this as due to a code defect in Sqagtres.dll. To resolve this issue, we would have to patch the SQL instance with Cumulative update 3 for SQL Server 2008 R2 SP2 as mentioned in below KB.
The hotfix download is available at http://support.microsoft.com/kb/2754552