How to load balance active/backup application server

Hi Experts

I have two application server. One is active and other is backup. I want, F5 LTM always sends all traffice to server-01 (active). If server-01 fails then it will send all traffic to server-02 (backup). What is the recommended way to achieve this requirement. I got few options in mind:

1- In pool configuration, define both servers but disable the server-02. In case of server-01 fails then enable the server-02 manually. But it needs manual configuration chanes on F5 LTM in case of server-01 fails.

2- Use priority activation group to achieve this.

Can any body point any other method?

Thanks