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This article is to share with you about how to modify CentOS ulimit system commands. The editor thinks it is very practical, so I share it with you to learn. I hope you can get something after reading this article.

The adjustment of the CentOS value (number of Linux file handles) in CentOS5 (RHEL5).

When deploying applications under Linux, we sometimes encounter the problem of Socket/File: Can't open so many files, for example, there is Squid as a proxy, when the file is opened to more than 900hrs, it can drop very quickly, and the web page may not be opened.

In fact, Linux is limited by file handles, and Linux is not very high by default, usually 1024, which can be easily reached by production servers.

View method

We can use CentOS ulimit-a to see all the limit values

[root@centos5] # Centos ulimit-a

Core file size (blocks,-c) 0

Data seg size (kbytes,-d) unlimited

Max nice (- e) 0

File size (blocks,-f) unlimited

Pending signals (- I) 4096

Max locked memory (kbytes,-l) 32

Max memory size (kbytes,-m) unlimited

Open files (- n) 1024

Pipe size (512 bytes,-p) 8

POSIX message queues (bytes,-Q) 819200

Max rt priority (- r) 0

Stack size (kbytes,-s) 10240

Cpu time (seconds,-t) unlimited

Max user processes (- u) 4096

Virtual memory (kbytes,-v) unlimited

File locks (- x) unlimited | | > / etc/security/limits.conf

You can change the file handle limit to soft 32768 and hard 65536. The first part of the configuration file refers to domain, which is set to an asterisk to represent the global situation. In addition, you can also make different restrictions for different users. The hard limit in this is the actual limit, while the soft limit, which is the warnning limit, only makes warning. In fact, the CentOS ulimit command itself has soft and hard settings, adding-H means hard, and adding-S means soft default shows soft limits. if you do not add it when you run the CentOS ulimit command to modify it, the two parameters are changed together. Take effect

You can see it when you re-log in after modification. My system is CentOS5.1. If modified, it will take effect immediately after re-logging in. You can check confirmation with CentOS ulimit-a.)

If you use squid, you need to add CentOS ulimit-HSn 65535 to the / etc/init.d/squid file. In addition, max_filedesc 16384 should be added to squid.conf.

The above is how to modify the CentOS ulimit system commands. The editor believes that there are some knowledge points that we may see or use in our daily work. I hope you can learn more from this article. For more details, please follow the industry information channel.

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