Installation guide

190 Chapter 14. Apache HTTP Server
14.5.3. PidFile
PidFile names the file where the server records its process ID (pid). Your Web server is set to record
its pid in /var/run/httpd.pid.
14.5.4. ScoreBoardFile
The ScoreBoardFile stores internal server process information, which is used for communication
between the parent server process and its child processes. Red Hat Linux uses shared memory to store
the ScoreBoardFile, the default of /etc/httpd/logs/apache_runtime_status is only used
as a fallback.
14.5.5. Timeout
Timeout defines, in seconds, the amount of time that your server will wait for receipts and trans-
missions during communications. Specifically, Timeout defines how long your server will wait to
receive a GET request, how long it will wait to receive TCP packets on a POST or PUT request and
how long it will wait between ACKs responding to TCP packets. Timeout is set to 300 seconds,
which is appropriate for most situations.
14.5.6. KeepAlive
KeepAlive sets whether your server will allow more than one request per connection (in other words,
it will allow persistent connections). KeepAlive can be used to prevent any one client from consum-
ing too much of the server’s resources.
By default Keepalive is set to off. If Keepalive is set to on and the server becomes very busy, the
server can quickly spawn the maximum number of child processes. In this situation, the server will
slow down significantly. If Keepalive is enabled, it is a good idea to set the the KeepAliveTimeout low
(see Section 14.5.8) and monitor the servers /var/log/httpd/error_log. This log will report
when the server is running out of child processes.
14.5.7. MaxKeepAliveRequests
This directive sets the maximum number of requests allowed per persistent connection. The Apache
Group recommends a high setting, which will improve your server’s performance. MaxKeepAliv-
eRequests is set to 100 by default, which should be appropriate for most situations.
14.5.8. KeepAliveTimeout
KeepAliveTimeout sets the number of seconds your server will wait after a request has been served
before it closes the connection. Once the server receives a request, the Timeout directive applies
instead.
14.5.9. MinSpareServers and MaxSpareServers
The Apache HTTP Server dynamically adapts to the perceived load by maintaining an appropriate
number of spare server processes based on the traffic. The server checks the number of servers waiting
for a request and kills some if there are more than MaxSpareServers or creates some if the number
of servers is less than MinSpareServers.