muthyala_51 (4/19/2013)

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Hi All,

I had an unexpected Auto failover from Principal to Mirror server.

We saw a network spike from 32MB to 1117MB during that period in the reports but the spike was normal during business working hours.

The mirror is configured in HIgh safety with Automatic failover with witness server mode(synch)

One task was happening during that time was copy of 1.8GB compressed backup copy to the principal server.

Does the network spike happens because of this? As we do this all the time, i dont expect this as the issue.

Could not found any specific errors in the log-

The errors we found were as below:

I would like to know why exactly the failover happened. Please someone can help me in analysing the rootcause of this failover.

Error 1:

The command failed because the database mirror is busy. Reissue the command later.

Error 2:

SQL Server has encountered 1 occurrence(s) of I/O requests taking longer than 15 seconds to complete on file [E:\templogfile\templog.ldf] in database [tempdb] (2). The OS file handle is 0x0000000000000514. The offset of the latest long I/O is: 0x000000000b5200

Error 3:

The mirroring connection to "TCP://XXXXXXX:5022" has timed out for database "dbname" after 10 seconds without a response. Check the service and network connections.