linux下的ulimit的研究

• 说明：

  文件描述符fd（File Descriptor）, 对于服务器来说，每一个TCP连接都要占用一个文件描述符。 普通用户默认限制的1024。通过下图查看到1000左右

• 参考

  https://www.cnblogs.com/embedded-linux/p/10225097.html https://juejin.cn/post/6844904005202608136 http://www.ruanyifeng.com/blog/2011/12/inode.html

• 查看当前用户限制

ulimit -n

• 查找进程

ps -aux | grep name

• 结果如下

$ cat /proc/2425532/limits
Limit                     Soft Limit           Hard Limit           Units
Max cpu time              unlimited            unlimited            seconds
Max file size             unlimited            unlimited            bytes
Max data size             unlimited            unlimited            bytes
Max stack size            8388608              unlimited            bytes
Max core file size        0                    unlimited            bytes
Max resident set          unlimited            unlimited            bytes
Max processes             256942               256942               processes
Max open files            1024                 1048576              files
Max locked memory         67108864             67108864             bytes
Max address space         unlimited            unlimited            bytes
Max file locks            unlimited            unlimited            locks
Max pending signals       256942               256942               signals
Max msgqueue size         819200               819200               bytes
Max nice priority         0                    0
Max realtime priority     0                    0
Max realtime timeout      unlimited            unlimited            us

• 修改系统最大打开文件数

$ vim /etc/security/limits.d/20-nproc.conf

*     soft   nofile    65535
*     hard   nofile    65535
*     soft   nproc     65535
*     hard   nproc     65535
root  soft   nproc     unlimited

$ reboot  # 重启服务器