ntp服务的安装
在rac环境中，会要求几个节点之间的时间差不能超时。一般如果超过30秒，节点很可能会重启。我们需要配置一个ntp时钟服务器，来给rac的各个节点进行时间同步。
在这里，我们以windows机器（192.168.1.189）做ntp server，以2台虚拟机上的rac节点（192.168.1.131和192.168.1.132）作为ntp client为例，进行配置：
1.下载windows版的ntp server——ntp-424p311502-foehr-v2-o-win32-setup
安装后，配置安装目录下的ntp.conf，主要配置的是下面这2个参数：
server 127.127.1.0 prefer
fudge 127.127.1.0 stratum 10
127.127.1.0表示是采用本机的时间作为ntp服务器时间，而不是去更上级的时间服务器去同步。
如下是我的windows机器上完整的ntp.config文件：
# Configuration File created by Windows Binary Distribution Installer Rev.: 1.22 mbg
# please check http://www.ntp.org for additional documentation and background information
# Use drift file
driftfile "d:\Program Files\NTP\etc\ntp.drift"
# your local system clock, could be used as a backup
# (this is only useful if you need to distribute time no matter how good or bad it is)
#server 127.127.1.0
# but it should operate at a high stratum level to let the clients know and force them to
# use any other timesource they may have.
#fudge 127.127.1.0 stratum 12
server 127.127.1.0 prefer
fudge 127.127.1.0 stratum 10
# End of generated ntp.conf --- Please edit this to suite your needs
注意配置完成从重启ntp服务：开始-运行-services.msc-Network Time Protocol Daemon。
2.配置linux端的client：
2.1 在/etc/ntp.config中修改：
server 192.168.1.189
fudge 192.168.1.189 stratum 10
注：如果有多个server服务器，可以写：
server 192.168.1.189 prefer
server 111.222.3.444
server 111.222.4.444
其中prefer表示该server是master server
注释掉：
server 127.127.1.0 # local clock
以下是我的linux机器上的/etc/ntp.conf：
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default nomodify notrap noquery
# Permit all access over the loopback interface. This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
# -- CLIENT NETWORK -------
# Permit systems on this network to synchronize with this
# time service. Do not permit those systems to modify the
# configuration of this service. Also, do not use those
# systems as peers for synchronization.
# restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# --- OUR TIMESERVERS -----
server 192.168.1.189
# --- NTP MULTICASTCLIENT ---
#multicastclient # listen on default 224.0.1.1
# restrict 224.0.1.1 mask 255.255.255.255 nomodify notrap
# restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap
# --- GENERAL CONFIGURATION ---
#
# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available. The
# default stratum is usually 3, but in this case we elect to use stratum
# 0. Since the server line does not have the prefer keyword, this driver
# is never used for synchronization, unless no other other
# synchronization source is available. In case the local host is
# controlled by some external source, such as an external oscillator or
# another protocol, the prefer keyword would cause the local host to
# disregard all other synchronization sources, unless the kernel
# modifications are in use and declare an unsynchronized condition.
#
#server 127.127.1.0 # local clock
fudge 192.168.1.189 stratum 10
#
# Drift file. Put this in a directory which the daemon can write to.
# No symbolic links allowed, either, since the daemon updates the file
# by creating a temporary in the same directory and then rename()'ing
# it to the file.
#
driftfile /var/lib/ntp/drift
broadcastdelay 0.008
#
# Keys file. If you want to diddle your server at run time, make a
# keys file (mode 600 for sure) and define the key number to be
# used for making requests.
#
# PLEASE DO NOT USE THE DEFAULT VALUES HERE. Pick your own, or remote
# systems might be able to reset your clock at will. Note also that
# ntpd is started with a -A flag, disabling authentication, that
# will have to be removed as well.
#
keys /etc/ntp/keys
2.2 修改/etc/ntp/ntpservers文件，把里面的server IP改为自己的ntp server的IP，也就是windows机器，下面是我的/etc/ntp/ntpservers：
#It is not recommended that you modify this file by hand.
192.168.1.189
2.3 修改/etc/hosts文件，加入windows主机的IP和主机名。
2.4 ps -ef |grep ntp 杀掉ntp进程。然后ntpdate 192.168.1.189手工做一次同步:
ntp 7466 1 0 17:13 ? 00:00:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid -g
root 7889 4976 0 17:17 pts/1 00:00:00 grep ntp
[root@rac3 init.d]#
[root@rac3 init.d]#
[root@rac3 init.d]# kill 7466
[root@rac3 init.d]#
[root@rac3 init.d]#
[root@rac3 init.d]#
[root@rac3 init.d]# ps -ef |grep ntp
root 7954 4976 0 17:17 pts/1 00:00:00 grep ntp
[root@rac3 init.d]# ntpdate 192.168.1.189
4 Jul 17:17:15 ntpdate[7955]: step time server 192.168.1.189 offset -0.656717 sec
[root@rac3 init.d]# /etc/init.d/ntpd start
Starting ntpd: [ OK ]
[root@rac3 init.d]#
2.5 启动ntp服务，并且加到run level 5：
Starting ntpd: [ OK ]
[root@rac3 init.d]#
[root@rac3 init.d]#
[root@rac3 init.d]#
[root@rac3 init.d]# ps -ef |grep ora_
root 7470 4976 0 17:13 pts/1 00:00:00 grep ora_
[root@rac3 init.d]# ps -ef |grep ntp
ntp 7466 1 0 17:13 ? 00:00:00 ntpd -u ntp:ntp -p /var/run/ntpd.pid -g
root 7472 4976 0 17:13 pts/1 00:00:00 grep ntp
[root@rac3 init.d]#
[root@rac3 ntp]# chkconfig --level 5 ntpd on
[root@rac3 ntp]#
[root@rac3 ntp]#
[root@rac3 ntp]# chkconfig --list |grep ntp
ntpd 0:off 1:off 2:off 3:off 4:off 5:on 6:off
注：如果偏差量大于1000秒，客户端不能自动与NTP master服务器进行同步。需要停ntpd服务后ntpdate手工同步，这也就是我们为什么在2.4步骤中先做手工同步的原因。
· 【文章发布信息】发表于： 2009-07-04 @ 17:23:39 · ||分类： ..experience, Working case
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noname 于 2009-07-08 @ 13:21:06 留言 ：
文件用rar格式压缩不大好吧
megan 于 2009-08-08 @ 13:25:39 留言 ：
貌似在client里配置fudge 192.168.1.189 stratum 10是错误的，这样是不会同步时间的；
仍应配置成fudge 127.127.1.0 stratum 10。
可以设置你的client机器时间比server机器快或慢几分钟，
然后重启client的ntp服务看时间是否会同步过来，
即可完成这个测试。
megan 于 2009-08-08 @ 13:34:25 留言 ：
呵呵，说得不清楚
我说的是这样不会自动同步，
手动同步当然是可以的。