To configure audit log options:
[edit system syslog] root@host# set archive files 2
[edit system syslog] root@host# set file syslog any any
[edit system syslog] root@host# set file syslog archive size 10000000
[edit system syslog] root@host# set file syslog structured-data
[edit] root@host# set security log cache
[edit] root@host# set security log mode event