How to Set Up Real-Time Data Sync with Sersync and Rsync on CentOS

1. Network Introduction

Two hosts are used for the experiment: qll251 as the Rsync server and Sersync server, and qll252 as the Rsync client. Both run CentOS 7.7, with the firewall disabled and SELinux set to disabled.

# cat /etc/redhat-release
CentOS Linux release 7.7.1908 (Core)
# systemctl stop firewalld && systemctl disable firewalld
# sed -i 's/SELINUX=enforcing/SELINUX=disabled/' /etc/selinux/config
# reboot
# getenforce
Disabled

2. Deployment

On the source host (qll251) deploy Sersync and Rsync services

Download the Sersync binary package:

# wget https://sersync.googlecode.com/files/sersync2.5.4_64bit_binary_stable_final.tar.gz

Extract the package and rename the directory:

# tar -zxvf sersync2.5.4_64bit_binary_stable_final.tar.gz
# mv GNU-Linux-x86/ sersync2.5.4

Edit /root/sersync2.5.4/confxml.xml to set the local backup path, remote IP (192.168.1.252), and authentication parameters:

<sersync>
  <localpath watch="/data">
    <remote ip="192.168.1.252" name="web"/>
  </localpath>
  <rsync>
    <commonParams params="-artuz"/>
    <auth start="true" users="rsync_user" passwordfile="/etc/rsync.mypass"/>
  </rsync>
</sersync>

Create the local backup directory and the Rsync password file:

# mkdir /data
# echo 123123 > /etc/rsync.mypass
# chmod 600 /etc/rsync.mypass

Install and start Rsync and Xinetd services:

# yum -y install rsync xinetd
# systemctl start rsyncd && systemctl enable rsyncd
# systemctl start xinetd && systemctl enable xinetd

On the client host (qll252) deploy the Rsync client

# yum -y install rsync

Edit /etc/rsyncd.conf with the following key settings:

uid = root
gid = root
address = 192.168.1.252
port = 873
hosts allow = 192.168.1.0/24
use chroot = yes
max connections = 5
pid file = /var/run/rsyncd.pid
lock file = /var/run/rsync.lock
log file = /var/log/rsyncd.log
motd file = /etc/rsyncd.motd
[web]
  path = /mybak
  comment = used for mysql-data
  read only = false
  list = yes
  auth users = rsync_user
  secrets file = /etc/rsync.passwd

Create the destination directory and the password file for the client:

# mkdir /mybak
# echo "rsync_user:123123" > /etc/rsync.passwd
# chmod 600 /etc/rsync.passwd

Start the Rsync daemon with the custom configuration:

# rsync --daemon --config=/etc/rsyncd.conf
# echo "rsync --daemon --config=/etc/rsyncd.conf" >> /etc/rc.local

3. Start Sersync Daemon for Data Sync

Perform a manual sync to verify the environment:

# rsync -avz /data [email protected]::web --password-file=/etc/rsync.mypass

After confirming success, launch the Sersync daemon:

# /root/sersync2.5.4/sersync2 -d -r -o /root/sersync2.5.4/confxml.xml

Real‑time synchronization can be observed on both machines.

To enable automatic start after reboot, add the daemon command to /etc/rc.local and ensure both /etc/rc.local and /etc/rc.d/rc.local are executable:

# chmod +x /etc/rc.d/rc.local
# reboot

With these steps, the two hosts achieve continuous, real‑time data synchronization using Sersync and Rsync.