Increasing the Number of Error Log
Files 
You can increase the number of error logs that are stored by the system as follows:
...
1. In the Enterprise Manager expand the Server and Management nodes. Select SQL Server Logs and then choose Action ® Configure
The Configure SQL Server Error Logs dialog box appears.
2.
Select Limiting the number of
the error logs before they are recycled.
Enter the number of logs you would like to the system to keep before they are
overwritten.
See also: