rsync+inotify实现数据的实时同步
一，简介：
1. rsync是类unix系统下的数据镜像备份工具——remote sync。一款快速增量备份工具 Remote Sync，远程同步 支持本地复制，或者与其他SSH、rsync主机同步。与传统的cp、tar备份方式相比，rsync具有安全性高、备份迅速、支持增量备份等优点，通过rsync可以解决对实时性要求不高的数据备份需求，例如定期的备份文件服务器数据到远端服务器，对本地磁盘定期做数据镜像等。随着应用系统规模的不断扩大，对数据的安全性和可靠性也提出的更好的要求，rsync在高端业务系统中也逐渐暴露出了很多不足，首先，rsync同步数据时，需要扫描所有文件后进行比对，进行差量传输。如果文件数量达到了百万甚至千万量级，扫描所有文件将是非常耗时的。而且正在发生变化的往往是其中很少的一部分，这是非常低效的方式。其次，rsync不能实时的去监测、同步数据，虽然它可以通过Linux守护进程的方式进行触发同步，但是两次触发动作一定会有时间差，这样就导致了服务端和客户端数据可能出现不一致，无法在应用故障时完全的恢复数据。基于以上原因，rsync+inotify组合出现了！
2. Inotify 是一种强大的、细粒度的、异步的文件系统事件监控机制，linux内核从2.6.13起，加入了Inotify支持，通过Inotify可以监控文件系统中添加、删除，修改、移动等各种细微事件，利用这个内核接口，第三方软件就可以监控文件系统下文件的各种变化情况，而inotify-tools就是这样的一个第三方软件。
在上面章节中，我们讲到，rsync可以实现触发式的文件同步，但是通过crontab守护进程方式进行触发，同步的数据和实际数据会有差异，而inotify可以监控文件系统的各种变化，当文件有任何变动时，就触发rsync同步，这样刚好解决了同步数据的实时性问题。
二，环境介绍：
| host | status | 系统内核版本 |
| 192.168.180.4 | client或源端 | CentOS release 6.8（2.6.32-642.3.1.el6.x86_64 ） |
| 192.168.180.3 | server或目标端 | CentOS release 6.4（2.6.32-358.el6.x86_64） |
三，具体步骤：
（一），先在目标服务器端安装rsync服务端；
1，关闭SELINUX
[root@GJB-UAT ~]# vim /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled
#SELINUX=enforcing
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
#SELINUXTYPE=targeted
12 [root@Monitor conf]# setenforce 0 ####立即生效
setenforce: SELinux is disabled
2，开启防火墙tcp873rsync默认的端口
[root@GJB-UAT ~]# vim /etc/sysconfig/iptables
-A INPUT -m state --state NEW -m tcp -p tcp --dport 873 -j ACCEPT
"/etc/sysconfig/iptables" 15L, 607C 已写入
[root@GJB-UAT ~]# /etc/init.d/iptables restart
[root@GJB-UAT ~]# iptables -L -n
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:80
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:873
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
target prot opt source destination
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
3，安装rsync服务端软件；
[root@GJB-UAT ~]# yum install rsync xinetd -y
Loaded plugins: fastestmirror
Determining fastest mirrors
* base: mirrors.cn99.com
* extras: mirrors.cn99.com
* updates: mirrors.cn99.com
base | 3.7 kB 00:00
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 4.3 MB 00:01
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package rsync.x86_64 0:3.0.6-12.el6 will be installed
---> Package xinetd.x86_64 2:2.3.14-40.el6 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
==========================================================================================================================
Package Arch Version Repository Size
==========================================================================================================================
Installing:
rsync x86_64 3.0.6-12.el6 base 335 k
xinetd x86_64 2:2.3.14-40.el6 base 122 k
Transaction Summary
==========================================================================================================================
Install 2 Package(s)
Total download size: 457 k
Installed size: 942 k
Is this ok [y/N]: y
Downloading Packages:
(1/2): rsync-3.0.6-12.el6.x86_64.rpm | 335 kB 00:00
(2/2): xinetd-2.3.14-40.el6.x86_64.rpm | 122 kB 00:00
--------------------------------------------------------------------------------------------------------------------------
Total 2.3 MB/s | 457 kB 00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : 2:xinetd-2.3.14-40.el6.x86_64 1/2
Installing : rsync-3.0.6-12.el6.x86_64 2/2
Verifying : rsync-3.0.6-12.el6.x86_64 1/2
Verifying : 2:xinetd-2.3.14-40.el6.x86_64 2/2
Installed:
rsync.x86_64 0:3.0.6-12.el6 xinetd.x86_64 2:2.3.14-40.el6
Complete!
[root@GJB-UAT ~]# rpm -qa|grep rsync
rsync-3.0.6-12.el6.x86_64
[root@GJB-UAT ~]# vim /etc/xinetd.d/rsync #####设置开机自启动 把disable=yes ,改成no
# default: off
# description: The rsync server is a good addition to an ftp server, as it \
# allows crc checksumming etc.
service rsync
{
disable = no
flags = IPv6
socket_type = stream
wait = no
user = root
server = /usr/bin/rsync
server_args = --daemon
log_on_failure += USERID
}
4,添加新用户和组并赋给相应的权限
[root@GJB-UAT ~]# groupadd rsync
[root@GJB-UAT ~]# useradd -g rsync.rsync
[root@GJB-UAT ~]# useradd -g rsync rsync
[root@GJB-UAT ~]# grep rsync /etc/passwd
rsync:x:501:501::/home/rsync:/bin/bash
[root@GJB-UAT ~]# mkdir /home/rsync/backup/
[root@GJB-UAT ~]# ll /home/rsync/
总用量 4
drwxr-xr-x. 2 root root 4096 1月 17 17:15 backup
[root@GJB-UAT ~]# chown -R rsync.rsync /home/rsync/backup/
[root@GJB-UAT ~]# ll /home/rsync/
总用量 4
drwxr-xr-x. 2 rsync rsync 4096 1月 17 17:15 backup
5，创建rsync daemon的配置文件
[root@GJB-UAT ~]# vim /etc/rsyncd.conf
uid = rsync
gid = rsync
use chroot = no
x connections = 40
timeout = 300
pid file = /var/run/rsyncd.pid
lock file = /var/run/rsyncd.lock
log file = /home/rsync/backup/rsyncd.log
[backup]
path = /home/rsync/backup/
ignore errors
read only = false
list = false
hosts allow = 192.168.180.0/24
auth users = rsync
secrets file =/etc/rsync.password
[root@GJB-UAT ~]# vim /etc/rsync.password
rsync:liqingbiao
[root@GJB-UAT ~]# chmod 600 /etc/rsync.password
[root@GJB-UAT ~]# chmod 600 /etc/rsyncd.conf
(二)安装rsync客户端（源端）
1，关闭SELINUX
[root@Monitor conf]# vim /etc/selinux/config
# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
# enforcing - SELinux security policy is enforced.
# permissive - SELinux prints warnings instead of enforcing.
# disabled - No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
# targeted - Targeted processes are protected,
# mls - Multi Level Security protection.
#SELINUXTYPE=targeted
2,开启防火墙tcp 873端口
[root@Monitor conf] vim /etc/sysconfig/iptables
-A INPUT -m state --state NEW -m tcp -p tcp --dport 873 -j ACCEPT
"/etc/sysconfig/iptables" 15L, 607C 已写入
[root@Monitor conf] /etc/init.d/iptables restart
[root@Monitor conf] iptables -L -n
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0 state RELATED,ESTABLISHED
ACCEPT icmp -- 0.0.0.0/0 0.0.0.0/0
ACCEPT all -- 0.0.0.0/0 0.0.0.0/0
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:22
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:80
ACCEPT tcp -- 0.0.0.0/0 0.0.0.0/0 state NEW tcp dpt:873
REJECT all -- 0.0.0.0/0 0.0.0.0/0 reject-with icmp-host-prohibited
Chain FORWARD (policy ACCEPT)
target prot opt source destination
REJECT all -- 0.0.0.0/0
3，安装配置rsync客户端软件
[root@Monitor conf]# yum install xinetd
已加载插件：fastestmirror
设置安装进程
Determining fastest mirrors
epel/metalink | 4.6 kB 00:00
* epel: mirrors.tuna.tsinghua.edu.cn
base | 3.7 kB 00:00
dockerrepo | 2.9 kB 00:00
epel | 4.3 kB 00:00
epel/primary_db | 5.9 MB 00:00
extras | 3.4 kB 00:00
updates | 3.4 kB 00:00
updates/primary_db | 4.3 MB 00:00
解决依赖关系
--> 执行事务检查
---> Package xinetd.x86_64 2:2.3.14-40.el6 will be 安装
--> 完成依赖关系计算
依赖关系解决
==========================================================================================================================
软件包 架构 版本 仓库 大小
==========================================================================================================================
正在安装:
xinetd x86_64 2:2.3.14-40.el6 base 122 k
事务概要
==========================================================================================================================
Install 1 Package(s)
总下载量：122 k
Installed size: 259 k
确定吗？[y/N]：y
下载软件包：
xinetd-2.3.14-40.el6.x86_64.rpm | 122 kB 00:00
运行 rpm_check_debug
执行事务测试
事务测试成功
执行事务
正在安装 : 2:xinetd-2.3.14-40.el6.x86_64 1/1
Verifying : 2:xinetd-2.3.14-40.el6.x86_64 1/1
已安装:
xinetd.x86_64 2:2.3.14-40.el6
完毕！
[root@Monitor conf]# rpm -qa|grep rsync
rsync-3.0.6-12.el6.x86_64
[root@Monitor logs]# vim /etc/xinetd.d/rsync
# default: off
# description: The rsync server is a good addition to an ftp server, as it \
# allows crc checksumming etc.
service rsync
{
disable = no
flags = IPv6
socket_type = stream
wait = no
user = root
server = /usr/bin/rsync
server_args = --daemon
log_on_failure += USERID
}
[root@Monitor conf]# /etc/init.d/xinetd start
正在启动 xinetd： [确定]
[root@Monitor logs]# netstat -lntp|grep xinetd
tcp 0 0 :::873 :::* LISTEN 38518/xinetd
4，创建认证文件
[root@Monitor logs]# vim /etc/rsyncd.passwd
liqingbiao
[root@Monitor conf]# chmod 600 /etc/rsyncd.passwd
5,测试源服务client器（192.168.180.4）到目标服务器服务端（192.168.180.3）之间的数据同步
[root@Monitor nginx]# rsync -avH --port=873 --progress /data/nginx/ [email protected]::backup --password-file=/etc/rsyncd.passwd
sending incremental file list
./
access.log
33777280 100% 39.93MB/s 0:00:00 (xfer#1, to-check=5/7)
error.log
201151 100% 227.88kB/s 0:00:00 (xfer#2, to-check=4/7)
nginx.access.log
278900324 100% 66.16MB/s 0:00:04 (xfer#3, to-check=3/7)
log/
log/access.log
0 100% 0.00kB/s 0:00:00 (xfer#4, to-check=1/7)
log/nginx.access.log
10521574 100% 66.89MB/s 0:00:00 (xfer#5, to-check=0/7)
sent 323439494 bytes received 386 bytes 71875528.89 bytes/sec
total size is 323400329 speedup is 1.00
[root@Monitor nginx]#
去192.168.180.3上查看backup定义的路径查看同步的文件完成，数据测试完成。
（三）安装Inotify-tools工具，实时出发rsync进行同步。
1，查看服务器的内核是否支持inotify(如果列出文件的目录，说明服务器内核支持inotify)
[root@Monitor nginx]# ll /proc/sys/fs/inotify
总用量 0
-rw-r--r-- 1 root root 0 1月 17 20:20 max_queued_events
-rw-r--r-- 1 root root 0 1月 17 20:20 max_user_instances
-rw-r--r-- 1 root root 0 1月 17 20:20 max_user_watches
2,安装编译工具和inotify-tools
[root@Monitor nginx]# yum install make gcc gcc-c++
已加载插件：fastestmirror
设置安装进程
Loading mirror speeds from cached hostfile
* epel: mirrors.tuna.tsinghua.edu.cn
包 1:make-3.81-23.el6.x86_64 已安装并且是最新版本
包 gcc-4.4.7-17.el6.x86_64 已安装并且是最新版本
包 gcc-c++-4.4.7-17.el6.x86_64 已安装并且是最新版本
无须任何处理
[root@Monitor nginx]# wget http://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
--2017-01-17 20:55:41-- http://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
正在解析主机 github.com... 192.30.253.113, 192.30.253.112
正在连接 github.com|192.30.253.113|:80... 已连接。
已发出 HTTP 请求，正在等待回应... 301 Moved Permanently
位置：https://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz [跟随至新的 URL]
--2017-01-17 20:55:41-- https://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
正在连接 github.com|192.30.253.113|:443... 已连接。
已发出 HTTP 请求，正在等待回应... 302 Found
位置：https://cloud.github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz [跟随至新的 URL]
--2017-01-17 20:55:43-- https://cloud.github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
正在解析主机 cloud.github.com... 54.192.127.169, 54.192.127.35, 54.192.127.201, ...
正在连接 cloud.github.com|54.192.127.169|:443... 已连接。
已发出 HTTP 请求，正在等待回应... 200 OK
长度：358772 (350K) [null]
正在保存至: “inotify-tools-3.14.tar.gz”
86% [=====================================================================> ] 310,532 91.0K/s eta(英国中部时95% [============================================================================> ] 343,300 87.8K/s eta(英国中部时100%[================================================================================>] 358,772 83.0K/s eta(英国中部时100%[================================================================================>] 358,772 83.0K/s in 4.2s
2017-01-17 20:56:00 (83.0 KB/s) - 已保存 “inotify-tools-3.14.tar.gz” [358772/358772])
[root@Monitor nginx]# tar xf inotify-tools-3.14.tar.gz
[root@Monitor nginx]# cd inotify-tools-3.14
[root@Monitor inotify-tools-3.14]# ./configure --prefix=/usr/local//inotify
[root@Monitor inotify-tools-3.14]#make && make install
3,设置系统环境变量，添加软连接。
[root@Monitor inotify-tools-3.14]# echo "PATH=/usr/local/inotify/bin:$PATH" >>/etc/profile.d/inotify.sh
[root@Monitor inotify-tools-3.14]# source /etc/profile.d/inotify.sh
[root@Monitor inotify-tools-3.14]# echo "/usr/local/inotify/lib" >/etc/ld.so.conf.d/inotify.conf
[root@Monitor inotify-tools-3.14]# ln -s /usr/local/inotify/include /usr/include/inotify
[root@Monitor inotify-tools-3.14]# sysctl -a | grep max_queued_events
4，修改inotify默认参数
[root@Monitor inotify-tools-3.14]# sysctl -a | grep max_queued_events
fs.inotify.max_queued_events = 99999999
[root@Monitor inotify-tools-3.14]# sysctl -a | grep max_user_watches
fs.inotify.max_user_watches = 99999999
fs.epoll.max_user_watches = 797306
[root@Monitor inotify-tools-3.14]# sysctl -a | grep max_user_instances
fs.inotify.max_user_instances = 65535
[root@Monitor inotify-tools-3.14]#
修改添加如下参数：
[root@Monitor inotify-tools-3.14]# vim /etc/sysctl.conf
fs.inotify.max_queued_events=99999999
fs.inotify.max_user_watches=99999999
fs.inotify.max_user_instances=65535
5，创建脚步，实时触发rsync进行同步
[root@Monitor inotify-tools-3.14]# vim /usr/local/inotify/rsync.sh
#!/bin/sh
#date:2017-01-17
#author:lqb
srcdir=/data/nginx
dstdir=backup
excludedir=/usr/local/inotify/exclude.list
rsyncuser=rsync
rsyncpassdir=/etc/rsyncd.passwd
dstip="192.168.180.3"
#for ip in $dstip
#do
rsync -avH --port=873 --progress --delete --exclude-from=$excludedir $srcdir $rsyncuser@$ip::$dstdir --password-file=$rsyncpassdir
#done
/usr/local/inotify/bin/inotifywait -mrq --timefmt '%d/%m/%y %H:%M' --format '%T %w%f%e' -e close_write,modify,delete,create,attrib,move $srcdir | while read file
do
for ip in $dstip
do
rsync -avH --port=873 --progress --delete --exclude-from=$excludedir $srcdir $rsyncuser@$ip::$dstdir --password-file=$rsyncpassdir
echo " ${file} was rsynced" >> /tmp/rsync.log 2>&1
done
done
[root@Monitor inotify-tools-3.14]#chmod +x /usr/local/inotify/rsync.sh
[root@Monitor inotify-tools-3.14]# /usr/local/inotify/rsync.sh
rsync: getaddrinfo: 873: No address associated with hostname
rsync error: error in socket IO (code 10) at clientserver.c(124) [sender=3.0.6]
sending incremental file list
nginx/
nginx/inotify-tools-3.14.tar.gz
358772 100% 34.54MB/s 0:00:00 (xfer#1, to-check=54/58)
nginx/nginx.access.log
40824576 14% 38.93MB/s 0:00:05
至此，数据进行同步。