Apache Web Server Performance Tuning In this window, you can set the Web server to optimize trade-offs between performance and CPU usage. Normally, however, the default values are good enough. 11.. NNuummbbeerr ooff PPrroocceesssseess Apache is built around a parent process, which accepts connections from clients, and one or more child processes. These child processes complete the requests and return the accessed page. The number of child processes changes dynamically, according to the number of connections to the Web server. The number of processes is limited by the value specified here. 11..11.. SSttaarrtt sseerrvveerrss The Web server will start with the number of child processes specified here. 11..22.. MMaaxx cclliieennttss ppeerr sseerrvveerrss The maximum number of child processes. Each client connection uses a child process, so this value indirectly controls how many clients can simultaneously connect to the Web server. If this value is too low, clients will be locked out, so be generous. This value is intended mostly as a safeguard against having a runaway web server crash the entire system. 11..33.. MMaaxx rreeqquueessttss ppeerr cchhiilldd A child process will exit after serving this number of accesses. It is intended as a failsafe against possible memory leaks. Currently, however, there are none known. 11..44.. MMiinniimmuumm ooff ssppaarree sseerrvveerrss Apache makes sure that there always are a few idle child processes, for handling transient load spikes. If fewer than this number of child processes are idle, more are started. 11..55.. MMaaxxiimmuumm ooff ssppaarree sseerrvveerrss Apache also makes sure that no more than this number of idle child processes exist. If more exist, some of them are killed. 22.. KKeeeeppss AAlliivvee To reduce the bandwidth used by Web traffic, HTTP was extended to allow more than one request within a single connection. This is called a _p_e_r_s_i_s_t_e_n_t _c_o_n_n_e_c_t_i_o_n or you can say that the connection is _k_e_p_t _a_l_i_v_e. 22..11.. KKeeeepp AAlliivvee If enabled, browsers can establish persistent connections. If disabled, the Web server will accept only one access per connection. 22..22.. KKeeeepp AAlliivvee TTiimmeeoouutt This specifies the number of seconds to wait for the next request in a persistent connection. If it is exceeded, the connection is closed. 22..33.. MMaaxx KKeeeepp AAlliivvee RReeqquueessttss The maximum number of requests allowed during a persistent connection. 33.. AAddvvaanncceedd TTuunniinngg 33..11.. TTiimmee oouutt The number of seconds the Web server will wait for a request to be sent, after a client has connected to the server. If a client connects, but does not send any requests, the client will be disconnected after this time (freeing the resources it was occupying).