Whenever a process opens a file (or a socket), a structure called a file descriptor is assigned until the file is closed. The OS limits the number of file descriptors that a given process can open, thus limiting the number of simultaneous connections the web server can have. How those settings are changed depends on the operating system. On Linux systems, you can read or modify /proc/sys/fs/file-max (using echo and cat as explained in the previous section). On Solaris systems, you must edit the value for rlim_fd_max in the /etc/system file. This change will require a reboot to take effect. You can find additional information at http://httpd.apache.org/docs/misc/descriptors.html. |