如何修改linux内核默认文件描述符最大同时打开数量?

me09

本人近来研究如何更改linux系统默认的同时打开的最大文件描述符数量。请各位能给小弟指导指导。或一起研究。谢谢！

me09

希望大家多多照顾！谢谢！

archangle

edit
/proc/sys/fs/file-max

me09

to 楼上： 光明使者 ：
非常感谢您的指教！谢谢1

me09

编译/proc/sys/fs/file-max 都需要那些条件？
1：是在内核编译前做/还是编译后做？
2：需要修改的文件模块和别的模块有多少耦合关系？
3：修改前需要做什么准备工作？
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就想到3条，本人是C新手upd大文件跨平台传输写了半个月，被...
请各位多多关照！谢谢！

hongzjx

修改内核参数:
fs.file-max

hongzjx

偶的系统缺省为:
fs.file-max = 209698

me09

to 精灵王
谢谢！
请问这样没个进程可以同时打开的文件描述符数量是不是也随之增加了
怎么计算？

hongzjx

Securing and Optimizing Linux: RedHat Edition -A Hands on Guide
Prev Chapter 6. Linux General Optimization Next

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6.9. The file-max parameter
The file-max file /proc/sys/fs/file-max sets the maximum number of file-handles that the Linux kernel will allocate. We generally tune this file to improve the number of open files by increasing the value of /proc/sys/fs/file-max to something reasonable like 256 for every 4M of RAM we have: i.e. for a machine with 128 MB of RAM, set it to 8192 - 128/4=32 32*256=8192.

The default setup for the file-max parameter under Red Hat Linux is: "4096" To adjust the value of file-max to 128 MB of RAM, type the following on your terminal:



          [root@deep] /# echo "8192" >;/proc/sys/fs/file-max
         

Add the above commands to the /etc/rc.d/rc.local script file and you'll not have to type it again the next time your server reboots.




Edit the /etc/sysctl.conf file and add the following line:           # Improve the number of open files
          fs.file-max = 8192
         

You must restart your network for the change to take effect. The command to manually restart the network is the following:           [root@deep] /# /etc/rc.d/init.d/network restart
         


Setting network parameters [ OK ] Bringing up interface lo [ OK ] Bringing up interface eth0 [ OK ] Bringing up interface eth1 [ OK ]


: When you regularly receive from your server a lot of messages with errors about running out of open files, you might want to raise this limit. The default value is 4096. A file server or web server needs a lot of open files.


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The /etc/nsswitch.conf file Up The ulimit parameter


看这里：

http://www.faqs.org/docs/securing/chap6sec72.html

me09

to 精灵王：
非常感谢您的帮助！


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希望大家多多指教谢谢！