In Linux systems, real-time synchronization of system data can be achieved through Rsync+sersync, which is more practical than the Rsync+Inotify-tools architecture. This article mainly introduces the detailed steps for installing rsync and sersync in Linux systems to achieve real-time data synchronization. Please refer to it for reference.

1. Why use Rsync+sersync architecture?

1. sersync is developed based on Inotify, a tool similar to Inotify-tools

2. Sersync can record the name of a specific file or directory that has changed (including addition, deletion, modification) in the monitored directory, and then when using rsync to synchronize, only the changed file or directory will be synchronized.

2. What is the difference between the two architectures Rsync+Inotify-tools and Rsync+sersync?

1. Rsync+Inotify-tools

(1): Inotify-tools can only record changes (including additions, deletions, and modifications) to the monitored directory, but does not record the specific files or directories that have changed;

(2): When rsync synchronizes, it does not know which file or directory has changed. It synchronizes the entire directory every time. When the amount of data is large, synchronization of the entire directory is very time-consuming (rsync requires Traverse the entire directory to find comparison files), so the efficiency is very low.

2. Rsync+sersync

(1): sersync can record the name of a specific file or directory that has changed (including addition, deletion, modification) in the monitored directory;

(2): When rsync synchronizes, it only synchronizes the changed file or directory (the data that changes each time is very small compared to the entire synchronized directory data. When rsync traverses and searches for comparison files, it is very fast. Fast), therefore, very efficient.

System Home editor reminds: When the amount of synchronized directory data is not large, it is recommended to use Rsync+Inotify-tools; when the amount of data is large (hundreds of G or even more than 1T) and there are many files, it is recommended to use Rsync+sersync.

illustrate:

Operating system: CentOS 5.X

Source server: 192.168.21.129

Target server: 192.168.21.127, 192.168.21.128

Purpose: Synchronize the /home/www.jb51.net directory on the source server to /home/www.jb51.net on the target server in real time

Specific operations:

Part 1: Operate on two target servers 192.168.21.127 and 192.168.21.128 respectively

1. Install Rsync server on two target servers respectively.

1. Close SELINUX

vi /etc/selinux/config #Edit firewall configuration file

The code is as follows:

#SELINUX=enforcing #Comment out

#SELINUXTYPE=targeted #Comment out

SELINUX=disabled #Add

:wq! #Save and exit

setenforce 0 #Take effect immediately

2. Open firewall tcp port 873 (Rsync default port)

vi /etc/sysconfig/iptables #Edit firewall configuration file

The code is as follows:

-A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 873 -j ACCEPT

:wq! #Save and exit

/etc/init.d/iptables restart #Finally restart the firewall to make the configuration take effect

3. Install Rsync server software

yum install rsync xinetd #Install

vi /etc/xinetd.d/rsync #Edit the configuration file and set up rsync on boot

The code is as follows:

disable = no #Change to no

:wq! #Save and exit

/etc/init.d/xinetd start #Start (Xinetd is used to manage the Rsync service in CentOS)

​