oracle rac ntp pre-install check

Oracle RAC has a pre-install check for ntpd running with -x option

Starting Linux NTP service:
/sbin/service ntpd start | stop | restart
Reference support.oracle.com Notid 551704.1
cat /etc/sysconfig/ntpd

# Drop root to id 'ntp:ntp' by default.
#OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid"
OPTIONS="-x -u ntp:ntp -p /var/run/ntpd.pid"
# Set to 'yes' to sync hw clock after successful ntpdate
SYNC_HWCLOCK=no
# Additional options for ntpdate
NTPDATE_OPTIONS=""