1.Have a Time server:10.203.94.101

server 127.127.1.0prefer
fudge 127.127.1.0 stratum 11
driftfile /var/lib/ntp/drift
broadcastdelay 0.008

----ALL Node

#vi /etc/ntp.conf
server 10.203.94.101 prefer
driftfile /var/lib/ntp/drift
broadcastdelay 0.008

* 12 *** /usr/sbin/ntpdate 10.203.94.101 >> /root/ntpdate.exe
*/2 * * * * /usr/sbin/ntpdate 10.203.94.101 >> /root/ntpdate.exe

2.Don't have a time server,using one node configure time server(node01)
swhygzhoudb01 10.203.94.141
swhygzhoudb02 10.203.94.142

[root@swhygzhoudb01]#vi /etc/ntp.conf
server 127.127.1.0
fudge 127.127.1.0 stratum 11
driftfile /var/lib/ntp/drift
broadcastdelay 0.008

[root@swhygzhoudb01]#/etc/init.d/ntpd start
[root@swhygzhoudb01]#chkconfig ?level 345 ntpd on
[root@swhygzhoudb01]#ntpq -p

[root@swhygzhoudb02]#vi /etc/ntp.conf
server 10.203.94.141 prefer
driftfile /var/lib/ntp/drift
broadcastdelay 0.008
[root@swhygzhoudb02]#service ntpd stop
[root@swhygzhoudb02]#ntpq -p
[root@swhygzhoudb02]#crontab -e
* 12 *** /usr/sbin/ntpdate 10.203.94.101 >> /root/ntpdate.exe
*/2 * * * * /usr/sbin/ntpdate 10.203.94.101 >> /root/ntpdate.exe

11.2.0.3 RAC 全过程--7.NTP Server