vim /etc/raddb/radiusd.conf

    #file = ${logdir}/radius.log  
    file = /dev/null

vim /etc/raddb/modules/detail

    #detailfile = ${radacctdir}/%{%{Packet-Src-IP-Address}:-%{Packet-Src-IPv6-Address}}/detail-%Y%m%d  
    detailfile = /dev/null