Linux内核从2.6.13开始，引入了inotify机制。通过intofity机制，能够对文件系统的变化进行监控，如对文件进行创建、删除、修改等操作，可以及时通知应用程序进行相关事件的处理。这种响应处理机制，避免了频繁的文件轮询任务，提高了任务的处理效率。
一、检查系统内核版本
[root@localhost tan]# uname -r
2.6.32-696.el6.x86_64
二、检查系统是否支持inotify
[root@localhost tan]# ls -lsart /proc/sys/fs/inotify
total 0
0 dr-xr-xr-x 0 root root 0 Jan 17 08:47 ..
0 dr-xr-xr-x 0 root root 0 Jan 17 08:53 .
0 -rw-r--r-- 1 root root 0 Jan 19 13:33 max_user_watches
0 -rw-r--r-- 1 root root 0 Jan 19 13:33 max_queued_events
0 -rw-r--r-- 1 root root 0 Jan 19 13:40 max_user_instances
[root@localhost tan]#
如果出现上面结果说明系统支持inotify。
三、下载安装（下载有点慢）
[root@localhost tan]#wget http://github.com/downloads/rvoicilas/inotify-tools/inotify-tools-3.14.tar.gz
[root@localhost tan]# tar -zvxf inotify-tools-3.14.tar.gz
[root@localhost tan]# cd inotify-tools-3.14
[root@localhost inotify-tools-3.14]# ./configure --prefix=/usr/local/inotify
[root@localhost inotify-tools-3.14]# make
[root@localhost inotify-tools-3.14]# make install
四、查看inotify默认参数
[root@localhost bin]# sysctl -a | grep max_queued_events
fs.inotify.max_queued_events = 16384
[root@localhost bin]# sysctl -a | grep max_user_watches
fs.inotify.max_user_watches = 8192
fs.epoll.max_user_watches = 798863
[root@localhost bin]# sysctl -a | grep max_user_instances
fs.inotify.max_user_instances = 128
五、修改inotify参数
1、命令修改
[root@localhost bin]# sysctl -w fs.inotify.max_user_instances=130
fs.inotify.max_user_instances = 130
2、文件修改
[root@localhost]# vi /etc/sysctl.conf
#添加如下代码
fs.inotify.max_user_instances=130
3、参数说明
- max_user_instances：每个用户创建inotify实例最大值
- max_queued_events：inotify队列最大长度，如果值太小，会出现错误，导致监控文件不准确
- max_user_watches：要知道同步的文件包含的目录数，可以用：
[root@localhost]# find /home/rain -type d|wc -l 统计，必须保证参数值大于统计结果（/home/tan/uploadFile/为同步文件目录）。
六、创建实时监控脚本 （file 里面放的需要监听的目录）
[root@localhost shell]# vi inotify.sh
/usr/local/inotify/bin/inotifywait -mrq -e modify,create,move,delete --fromfile '/root/shell/file' --timefmt '%y-%m-%d %H:%M' --format '%T %w%f %e' --outfile '/home/tan/inotify.log'
[root@localhost shell]# vi file
/home/tan
@/home/tan/uploadFile
inotifywait常用参数：
- –timefmt 时间格式
- %y年 %m月 %d日 %H小时 %M分钟
- –format 输出格式
- %T时间 %w路径 %f文件名 %e状态
- -m 始终保持监听状态，默认触发事件即退出。
- -r 递归查询目录
- -q 打印出监控事件
- -e 定义监控的事件，可用参数：
- open 打开文件
- access 访问文件
- modify 修改文件
- delete 删除文件
- create 新建文件
- attrb 属性变更
事件 描述
access 访问，读取文件。
modify 修改，文件内容被修改。
attrib 属性，文件元数据被修改。
move 移动，对文件进行移动操作。
create 创建，生成新文件
open 打开，对文件进行打开操作。
close 关闭，对文件进行关闭操作。
delete 删除，文件被删除。
七：实例操作
1、首先启动监听脚本，权限问题的话先：chmod 755 inotify.sh
[root@localhost shell]# ./inotify.sh
我在监听的目录中上传文件,没截图，自己想象吧
[root@localhost tan]# cat inotify.log
18-01-19 15:07 /home/tan/uploadfile/test//ssh.txt CREATE
18-01-19 15:13 /home/tan/uploadfile/test/QQ20180119143826.png CREATE
这里可以看到打印的日志了。
八、附
1、inotifywait
使用方法和参数说明： 使用命令help就行
[root@localhost bin]# ./inotifywait -h
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
2、inotifywatch
使用方法和参数说明：
[root@localhost bin]# ./inotifywatch -h
inotifywatch 3.14
Gather filesystem usage statistics using inotify.
Usage: inotifywatch [ options ] file1 [ file2 ] [ ... ]
Options:
-h|--help Show this help text.
-v|--verbose Be verbose.
@<file> Exclude the specified file from being watched.
--fromfile <file>
Read files to watch from <file> or `-' for stdin.
--exclude <pattern>
Exclude all events on files matching the extended regular
expression <pattern>.
--excludei <pattern>
Like --exclude but case insensitive.
-z|--zero
In the final table of results, output rows and columns even
if they consist only of zeros (the default is to not output
these rows and columns).
-r|--recursive Watch directories recursively.
-t|--timeout <seconds>
Listen only for specified amount of time in seconds; if
omitted or 0, inotifywatch will execute until receiving an
interrupt signal.
-e|--event <event1> [ -e|--event <event2> ... ]
Listen for specific event(s). If omitted, all events are
listened for.
-a|--ascending <event>
Sort ascending by a particular event, or `total'.
-d|--descending <event>
Sort descending by a particular event, or `total'.
Exit status:
0 - Exited normally.
1 - Some error occurred.
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