Recently we came across unexpected cluster fail over of one of our servers. It was required to get the exact reason for it. I analyzed the sql server and windows logs. There was no traces of failure neither i found any major issue in the logs that may lead to fail over. However an entry in the logs caught my attention and it was following message
Using ‘odsole70.dll’ version ‘2009.100.1600’ to execute extended stored procedure ‘sp_OACreate’. This is an informational message only; no user action is required.
I googled it and came to know that it is culprit of event. According to its BOL page
You call some Automation procedures from a SQL Server common language runtime (CLR) object, such as sp_OACreate. In this situation, SQL Server may unexpectedly crash.
Note This issue also occurs when a CLR object calls a Transact-SQL procedure that calls Automation procedures.
It applies to SQL Server 2005, SQL Server 2008, SQL Server 2008 R2, and SQL Server 2012. More detail can be found here.
Now we have to trace the call and modify it to avoid the accidental fail over.