Is there a possibility configure primary and backup aaa radius servers in cisco ASA 5516?
AAA-requests are always directed to only one server (primary) and only if it is unavailable to the second radius server (backup).
That is standard setup, if you looking to Loadbalance primary and secondary you need to do Loadbalancer ( to split the load between AAA Servers).
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Could you please advise on the specific configuration commands responsible for this policy?
Its not be done on the box, you need external Loadbalancer out of the box to do this work.
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