Server time synchronization of RAC

After two RAC configuration failures, I finally decided to start to stabilize and lay a solid foundation step by step to fully understand every detail of RAC, so I started a comprehensive study of the big talk RAC, and refused to let go of any details: today, I saw that the usage of configuring server nodes in "big talk RAC" is not the same as that of using cron scheduled tasks. So I found some documents and learned from them. I can refer to the following link:

Http://server.e800.com.cn/articles/2007/418/1176833223563138796_1.html

Http://blog.csdn.net/tianlesoftware/archive/2010/02/21/5315587.aspx

 

1: The article explains why to set up a time server and synchronize them:

Synchronization is even more important when it comes to security devices on the network. The logs generated by these devices must reflect the accurate time. Especially when processing busy data, if the time is not synchronized, it is almost impossible to associate logs from different sources. Once log files are not connected, security-related tools are useless. Non-synchronous networks mean that enterprises have to spend a lot of time manually tracking security events. Now let's take a look at how to synchronize the network and make the security log show accurate time.

2: InstallationNTPService:

The article has introduced how to compile the source code for installation. The following excerpt shows how to directly check whether the source code package exists and then install the RPM package:

How to install the time server on as4 (also applicable to RedHat and other Fedora Core versions). If you want to get the latest NTP version, you can download the tar package and compile it by yourself, here we will only introduce the NTP service software installed in RPM mode.
The NTP version of as4 is 4.2.0. You can run the following command to check whether the software package has been installed:
# Rpm-Qa | grep NTP
Ntp-4.2.0.a.20040617-4.2

If no installation is found, install the software on the CD. Run the following command to install the ntp rpm package:
# Rpm-IVH ntp-4.2.0.a.20040617-4.2.i386.rpm

3: Let's take a look at synchronization.NTPOf3Working Mode:
(1) active/passive symmetric mode (broadcast/Multicast): one-to-one connection. Both parties can synchronize or be synchronized by the other party, the first party that sends a request to establish a connection works in active mode, and the other party works in passive mode. This method is suitable for configuring redundant time servers and provides higher precision to the host.

(2) customer/Server mode (Client/Server): it is basically the same as the master/Passive mode. The only difference is that the client can be synchronized by the server, but the server cannot be synchronized by the customer.

(3) broadcast mode: one-to-many connections. The server actively sends time information regardless of the mode in which the customer works, and the customer adjusts the time based on the information. In this case, the network delay D2 is ignored, therefore, there is a loss in accuracy, but it can be applied within seconds. Broadcast mode and easy configuration. However, this method is not highly accurate and can be used if the time precision requirement is not very high.

4: DahuaRACThe broadcast mode of server time synchronization is as follows:

 

1. If there is a time server in the company's network: 10.85.10.80, you only need to modify the NTP service configuration file on each node so that each node and time server can be synchronized.

# Vi/etc/NTP. conf

Server 10.85.10.80 prefer

Driftfile/var/lib/NTP/drift

Broadcastdelay 0.008

Restart the NTP service after modification.

#/Etc/init. d/ntpd restart

2. If there is no time service, you can use one of the two RAC nodes as the server. The other one can be synchronized with this server.

Add node1 as the server. The IP address is 10.85.10.119. modify the configuration file.

# Vi/etc/NTP. conf

Server 127.127.1.0 -- local clock

Fudge 127.127.1.0 stratum 11

Broadcastdelay 0.008

Synchronize node2 with node1. Modify the NTP configuration file of node2

# Vi/etc/NTP. conf

Server 10.85.10.119 prefer

Driftfile/var/lib/NTP/drift

Broadcastdelay 0.008

Restart the NTP service after modification.

#/Etc/init. d/ntpd restart

The most fundamental thing about server time synchronization is finally very clear, to be continued .... I made the complete supplement into an attachment. You can download the attachment.