inotify+rsync做实时同步

inotify的下载地址：https://github.com/rvoicilas/inotify-tools

下载的版本为inotify-tools.3.14  将下载的工具规范地放在一个地方，比如放到/home/goser/tools/下

查看linux系统内核是否支持inotify,只要包含下面三个文件代表系统是支持的

[root@nfs-server inotify-tools-3.14]# ll  /proc/sys/fs/inotify/
总用量 0
-rw-r--r-- 1 root root 0 9月  15 11:05 max_queued_events
-rw-r--r-- 1 root root 0 9月  15 11:05 max_user_instances
-rw-r--r-- 1 root root 0 9月  15 11:05 max_user_watches

切到/home/goser/tools/下，解压  tar  zxf  inotify-tools-3.14.tar.gz 

因为这是c语言编译的工具，要用make install 安装，安装顺序为

cd  inotify-tools-3.14
./configure --prefix=/usr/local/inotify-tools-3.14
make && make  install

编译完成后需要做个软连接

ln -s /usr/local/inotify-tools-3.14/ /usr/local/inotify-tools

inotify主要的就是其下面的bin目录中的inotifywait和inotifywatch,这个inotifywait只要监控的目录有变化，如文件的删除、创建、修改等操作的时候，就会触发实时备份。。。

[root@nfs-server inotify-tools-3.14]# ll  /usr/local/inotify-tools/bin/
总用量 88
-rwxr-xr-x 1 root root 44287 9月  15 11:13 inotifywait
-rwxr-xr-x 1 root root 41409 9月  15 11:13 inotifywatch

 查看inotifywait的帮助，可以查看其可跟的参数选项：

[root@nfs-server ~]# /usr/local/inotify-tools/bin/inotifywait --help
inotifywait 3.14
Wait for a particular event on a file or set of files.
Usage: inotifywait [ options ] file1 [ file2 ] [ file3 ] [ ... ]
Options:
        -h|--help       Show this help text.
        @<file>         Exclude the specified file from being watched.
        --exclude <pattern>
                        Exclude all events on files matching the
                        extended regular expression <pattern>.
        --excludei <pattern>
                        Like --exclude but case insensitive.
        -m|--monitor    Keep listening for events forever.  Without
                        this option, inotifywait will exit after one
                        event is received.
        -d|--daemon     Same as --monitor, except run in the background
                        logging events to a file specified by --outfile.
                        Implies --syslog.
        -r|--recursive  Watch directories recursively.
        --fromfile <file>
                        Read files to watch from <file> or `-' for stdin.
        -o|--outfile <file>
                        Print events to <file> rather than stdout.
        -s|--syslog     Send errors to syslog rather than stderr.
        -q|--quiet      Print less (only print events).
        -qq             Print nothing (not even events).
        --format <fmt>  Print using a specified printf-like format
                        string; read the man page for more details.
        --timefmt <fmt> strftime-compatible format string for use with
                        %T in --format string.
        -c|--csv        Print events in CSV format.
        -t|--timeout <seconds>
                        When listening for a single event, time out after
                        waiting for an event for <seconds> seconds.
                        If <seconds> is 0, inotifywait will never time out.
        -e|--event <event1> [ -e|--event <event2> ... ]
                Listen for specific event(s).  If omitted, all events are 
                listened for.

Exit status:
        0  -  An event you asked to watch for was received.
        1  -  An event you did not ask to watch for was received
              (usually delete_self or unmount), or some error occurred.
        2  -  The --timeout option was given and no events occurred
              in the specified interval of time.

Events:
        access          file or directory contents were read
        modify          file or directory contents were written
        attrib          file or directory attributes changed
        close_write     file or directory closed, after being opened in
                        writeable mode
        close_nowrite   file or directory closed, after being opened in
                        read-only mode
        close           file or directory closed, regardless of read/write mode
        open            file or directory opened
        moved_to        file or directory moved to watched directory
        moved_from      file or directory moved from watched directory
        move            file or directory moved to or from watched directory
        create          file or directory created within watched directory
        delete          file or directory deleted within watched directory
        delete_self     file or directory was deleted
        unmount         file system containing file or directory unmounted

监控测试 

[root@nfs-server ~]# /usr/local/inotify-tools/bin/inotifywait -mrq --timefmt '%d%m%y %H:%M' --format '%T %w%f' -e create,delete,close_write  /data/   在监控中的话，会话窗口是堵塞的，一直在监控着事件的发生。

inotify+rsync企业应用

这个应用支持的并发数为每秒200-300个文件并发，如果超过这个范围，要用到架构drbd了，不过一般的中小网站基本上没问题。

1、在nfs服务器上部署inotify，监控共享目录的变化，向rsync daemon服务上做实时同步

　　部署过程如上面的过程，这里不再赘述

2、创建inotify脚本，做实时同步

[root@nfs-server ~]# vim /server/scripts/inotify.sh

#!/bin/bash
inotify=/usr/local/inotify-tools/bin/inotifywait
$inotify -mqr --format '%w%f' -e create,delete,close_write /data/ \
|while read file
do
  cd / &&
  rsync -az ./data  --delete rsync_backup@192.168.1.104::backup/ \
  --password-file=/etc/rsync.password
done

3、位nfs服务创建为rsync同步的密码文件

[root@nfs-server data]# echo 'oldboy'>/etc/rsync.password
[root@nfs-server data]# chmod  600  /etc/rsync.password 

4、脚本测试

sh -x  /server/scripts/inotify.sh 

5、测试没问题了，让inotify.sh脚本做后台运行

[root@nfs-server ~]# /bin/sh /server/scripts/inotify.sh  &

6、将此后台运行的命令加入到/etc/rc.local中，方便服务器重启后也能进行后台运行inotify实时同步。

[root@nfs-server ~]# vi /etc/rc.local 

#!/bin/sh
#
# This script will be executed *after* all the other init scripts.
# You can put your own initialization stuff in here if you don't
# want to do the full Sys V style init stuff.

touch /var/lock/subsys/local
>/etc/udev/rules.d/70-persistent-net.rules
/etc/init.d/rpcbind start
/etc/init.d/nfs start
/bin/sh /server/scripts/inotify.sh  &

7、对inotify的优化

在/proc/sys/fs/inotify/下有三个文件，对inotify的机制有限制，可对这三个文件做下优化

max_user_watches   设置可以监控的文件数量  默认值是8192   这个值应该很小了，需要优化

max_queued_events    设置队列可容纳的事件数量   默认值是16384   这个值也很小需要优化

max_user_instances    设置每个用户可运行的inotifywait或inotifywatch命令的进程数，默认值是128  这个值应该不小了  就不需要优化了

优化如下：

[root@nfs-server ~]# echo '50000000'>/proc/sys/fs/inotify/max_user_watches 
[root@nfs-server ~]# echo '50000000'>/proc/sys/fs/inotify/max_queued_events