The file-max parameter

Securing and Optimizing Linux: RedHat Edition -A Hands on Guide
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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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