概述

前文说明了如何使用 Rsync 搭配 inotify-tools 完成实时的单向数据同步，在一些特殊场景中，可能还会使用到双向同步。

在软件搭配上：

• inotify-tools - 文件系统监视程序
• Unison - 文件同步工具

环境准备

• RL 8.10 和 RL 10.3 都需要安装了 Unison 和 inotify-tools
• 两台机器使用 SSH 协议完成了双向免密验证登陆
• Unison 底层依赖 ocaml 编译语言

# inotify-tools 软件包信息
Shell (192.168.100.20)> dnf info inotify-tools
Last metadata expiration check: 0:26:11 ago on Sun 08 Nov 2026 08:14:20 PM CST.
Installed Packages
Name         : inotify-tools
Version      : 3.14
Release      : 19.el8
Architecture : x86_64
Size         : 120 k
Source       : inotify-tools-3.14-19.el8.src.rpm
Repository   : @System
From repo    : epel
Summary      : Command line utilities for inotify
URL          : http://inotify-tools.sourceforge.net/
License      : GPLv2
Description  : inotify-tools is a set of command-line programs for Linux providing
             : a simple interface to inotify. These programs can be used to monitor
             : and act upon filesystem events.

# 免密验证登陆
Shell (192.168.100.20)> ssh -p 22 -i /root/.ssh/id_rsa riu@192.168.100.21
Last login: Sun Nov  8 20:58:13 2026

RL 10.3 环境验证：

# inotify-tools 软件包信息
Shell (192.168.100.21)> dnf5 info inotify-tools
Updating and loading repositories:
Repositories loaded.
Installed packages
Name            : inotify-tools
Epoch           : 0
Version         : 4.23.9.0
Release         : 4.el10_1
Architecture    : x86_64
Installed size  : 209.8 KiB
Source          : inotify-tools-4.23.9.0-4.el10_1.src.rpm
From repository : epel
Summary         : Command line utilities for inotify
URL             : https://github.com/inotify-tools/inotify-tools
License         : GPL-2.0-only AND GPL-2.0-only WITH Linux-syscall-note AND LGPL-2.1-or-later
Description     : inotify-tools is a set of command-line programs for Linux providing
                : a simple interface to inotify. These programs can be used to monitor
                : and act upon filesystem events.
Vendor          : Fedora Project

# 免密验证登陆
Shell (192.168.100.21)> ssh -p 22 -i /root/.ssh/r8_id_rsa r8riu@192.168.100.20
Last login: Sun Nov  8 21:29:10 2026

RL 8 安装 Unison

ocaml 的安装步骤如下：

Shell > wget -c https://github.com/ocaml/ocaml/archive/refs/tags/4.14.2.tar.gz

Shell > tar -vxf 4.14.2.tar.gz -C /usr/local/src/

Shell > cd /usr/local/src/ocaml-4.14.2/

Shell > ./configure --prefix=/usr/local/ocaml && make world opt && make install
...

Shell > ls -l /usr/local/ocaml/
total 16
drwxr-xr-x 2 root root 4096 Nov  9 00:04 bin
drwxr-xr-x 3 root root 4096 Nov  9 00:04 lib
drwxr-xr-x 4 root root 4096 Nov  9 00:04 man
drwxr-xr-x 3 root root 4096 Nov  9 00:04 share

Shell > echo PATH=$PATH:/usr/local/ocaml/bin >> /etc/profile

Shell > . /etc/profile

Unison 的安装步骤如下

Shell > wget -c https://github.com/bcpierce00/unison/archive/refs/tags/v2.54.0.tar.gz

Shell > tar -vxf v2.54.0.tar.gz -C /usr/local/src/

Shell > cd /usr/local/src/unison-2.54.0/

Shell > make

Shell > ls src/unison
src/unison

Shell > cp -p src/unison /usr/local/bin/

RL 10 安装 Unison

ocaml 的安装步骤如下：

Shell > wget -c https://github.com/ocaml/ocaml/archive/refs/tags/4.14.2.tar.gz

Shell > tar -vxf 4.14.2.tar.gz -C /usr/local/src/

Shell > cd /usr/local/src/ocaml-4.14.2/

Shell > ./configure --prefix=/usr/local/ocaml && make world opt && make install
...

Shell > ls -l /usr/local/ocaml/
total 16
drwxr-xr-x 2 root root 4096 Nov  9 00:14 bin
drwxr-xr-x 3 root root 4096 Nov  9 00:14 lib
drwxr-xr-x 4 root root 4096 Nov  9 00:14 man
drwxr-xr-x 3 root root 4096 Nov  9 00:14 share

Shell > echo PATH=$PATH:/usr/local/ocaml/bin >> /etc/profile

Shell > . /etc/profile

Unison 的安装步骤如下

Shell > wget -c https://github.com/bcpierce00/unison/archive/refs/tags/v2.54.0.tar.gz

Shell > tar -vxf v2.54.0.tar.gz -C /usr/local/src/

Shell > cd /usr/local/src/unison-2.54.0/

Shell > make

Shell > ls src/unison
src/unison

Shell > cp -p src/unison /usr/local/bin/

演示

需求：RL 8.10 的 /dir1/ 目录与 RL 10.3 的 /dir2/ 目录实现双向同步。

配置 RL 8.10

Shell > mkdir /dir1/

Shell > setfacl -m u:r8riu:rwx /dir1/

Shell > vim /root/sync1.sh
#!/bin/bash
inotifywait -mrq -e create,delete,modify,move /dir1/ | while read directory event file
do
    /usr/local/bin/unison -batch /dir1/ ssh://riu@192.168.100.21:22//dir2 -sshargs "-i /root/.ssh/id_rsa" &>> /tmp/sync1.log
done

Shell > chmod +x /root/sync1.sh

Shell > bash /root/sync1.sh &

Shell > jobs -l

配置 RL 10.3

Shell > mkdir /dir2/

Shell > setfacl -m u:riu:rwx /dir2/

Shell > vim /root/sync2.sh
#!/bin/bash
inotifywait -mrq -e create,delete,modify,move /dir2/ | while read directory event file
do
    /usr/local/bin/unison -batch /dir2/ ssh://r8riu@192.168.100.20:22//dir1 -sshargs "-i /root/.ssh/r8_id_rsa" &>> /tmp/sync2.log
done

Shell > chmod +x /root/sync2.sh

Shell > bash /root/sync2.sh &

Shell > jobs -l

注意点：

• 双向同步时，双方服务器的脚本必须都需要启动，否则可能会报错
• 注意双向同步时的用户权限设置
• 使用 unison 命令时，注意不要漏掉目标目录路径的前缀 "/"，如 /usr/local/bin/unison -batch /dir2/ ssh://r8riu@192.168.100.20:22//dir1 -sshargs "-i /root/.ssh/r8_id_rsa" 中的 /dir1
• 注意观察日志文件的内容，未来排查错误时很有用
• 注意观察 Bash 脚本的状态，处于 Running 是正常状态，处于 Stopped 则需要排查错误

尝试下：

Shell (192.168.100.20)> touch /dir1/{R8-file,R8-f2}

Shell (192.168.100.21)> touch /dir2/R10-file

同步完成：

Shell (192.168.100.20)> ls /dir1/
R10-file  R8-f2  R8-file

Shell (192.168.100.21)> ls /dir2/
R10-file  R8-f2  R8-file

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