在对一个大磁盘进行inotify监听时，爆出如下错误：
Failed to watch /mnt/;
upper limit on inotify watches reached!
Please increase the amount of inotify watches allowed per user via `/proc/sys/fs/inotify/max_user_watches’.
cat一下这个文件，默认值是8192；df -i看看inode数量，远远大过这个值~
echo 8192000 > /proc/sys/fs/inotify/max_user_watches即可~
