In a test lab, we ran into a situation where the connection between our Cisco Access Registrar (AAA) server and MySQL server was timing out. This forced the server to reconnect and resulted in the following errors:

 name/radius/1 Error Server 0 ODBC client (DataSource 'my_odbc', Connection 8): SQLExecute failed: SQLState:08S01 NativeError:2006 ErrorText:[MySQL][ODBC 3.51 Driver][mysqld-5.0.21-log] MySQL server has gone away
name/radius/1 Error Server 0 Service odbc has no active remote servers available

Obviously, the MySQL server was still there, but after the wait_timeout expires, the server severs the idle connections. By default, the wait_timeout is set to 8 hours. This is obviously much longer than is usually necessary, but in our test lab, it caused problems every morning.

The fix is