Creating an Audit Report to monitor the System administrator

 Hello, I have been given the task of creating an audit report which will monitor what the system administrator does.  I know turning on audit on tables will affect the performane of the system.  Which tables would i need to turn on audit on enbale to access audit infomration for the system administrator responsibilities.

Are there any other ways to go about creating and audit report for the system administrator.

Thanks

sherrarddr@jncb.com