Chapter 24. Apache HTTP Server Configuration248The PID File value corresponds to the PidFile31 directive. This directive sets the file in which theserver records its process ID (pid). This file should only be readable by root. In most cases, it shouldbe left to the default value.The Core Dump Directory value corresponds to the CoreDumpDirectory32 directive. The ApacheHTTP Server tries to switch to this directory before executing a core dump. The default value is theServerRoot. However, if the user that the server runs as can not write to this directory, the coredump can not be written. Change this value to a directory writable by the user the server runs as, ifyou want to write the core dumps to disk for debugging purposes.The User value corresponds to the User33 directive. It sets the userid used by the server to answerrequests. This user's settings determine the server's access. Any files inaccessible to this user arealso inaccessible to your website's visitors. The default for User is apache.The user should only have privileges so that it can access files which are supposed to be visible tothe outside world. The user is also the owner of any CGI processes spawned by the server. The usershould not be allowed to execute any code which is not intended to be in response to HTTP requests.WarningUnless you know exactly what you are doing, do not set the User directive to root. Usingroot as the User creates large security holes for your Web server.The parent httpd process first runs as root during normal operations, but is then immediately handedoff to the apache user. The server must start as root because it needs to bind to a port below 1024.Ports below 1024 are reserved for system use, so they can not be used by anyone but root. Once theserver has attached itself to its port, however, it hands the process off to the apache user before itaccepts any connection requests.The Group value corresponds to the Group34 directive. The Group directive is similar to the Userdirective. Group sets the group under which the server answers requests. The default group is alsoapache.24.5. Performance TuningClick on the Performance Tuning tab to configure the maximum number of child server processesyou want and to configure the Apache HTTP Server options for client connections. The default settingsfor these options are appropriate for most situations. Altering these settings may affect the overallperformance of your Web server.31 http://httpd.apache.org/docs-2.0/mod/mpm_common.html#pidfile32 http://httpd.apache.org/docs-2.0/mod/mpm_common.html#coredumpdirectory33 http://httpd.apache.org/docs-2.0/mod/mpm_common.html#user34 http://httpd.apache.org/docs-2.0/mod/mpm_common.html#group
