iTP Secure WebServer System Administrators Guide (Version 7.5+)

require more detailed planning. The best way to avoid these types of problems is to make all
the httpd servers static servers.
Configuring the PATHMON Environment
The configuration of the iTP Secure WebServer PATHMON environment is specified in the
httpd.config file. You specify the configuration file when you start the iTP Secure WebServer
process.
The httpd.config file consists of keyword-value pairs. The sample configuration file
httpd.config.sample is included in the /usr/tandem/webserver/conf directory. That
file contains all keywords along with their default values and ranges.
The configuration file can contain spaces, tabs, blank lines, and lines that start with a pound sign
(#), which identifies the line as a comment. The keywords are case-sensitive and must be spelled
exactly as defined or they will not be recognized. A keyword must be followed by a valid value.
For an example of the httpd.config file, see “Configuring the iTP Secure WebServer” (page 94).
The example includes commands for configuring several processes that are essential in the HP
environment for the iTP Secure WebServer. The configuration file creates a PATHMON process and
configures the application servers and the Distributor process.
For detailed descriptions of all the configuration directives you can specify in the server configuration
file (httpd.config), see “Configuration Directives” (page 198).
To understand the configuration file, you must know the basic NonStop TS/MP architecture and
characteristics of the PATHMON environment. If you are not already familiar with the basics of using
NonStop TS/MP, see the TS/MP System Management Manual
Threading Considerations for the httpd Server
You can use two techniques, individually or in combination, to allow the iTP Secure WebServer
to handle many requests in parallel:
• Allow for a large number of servers in the httpd server class.
• Allow each server to handle multiple requests in parallel.
To allow for multiple servers, use the Maxservers command in the Server directive. This command
specifies the total number of servers in the class. If you want each server to besingle-threaded, the
value of Maxservers should be large enough to accommodate the maximum number of concurrent
requests your WebServer must be able to handle.
To allow for multithreading in each server process, use the TANDEM_RECEIVE_DEPTH environment
variable. (The Env command in the Server directive enables you to specify environment variables.)
The value of TANDEM_RECEIVE_DEPTH is the maximum number of requests a single httpd or
servlet process can handle.
NOTE: Although the receive depth is conceptually similar to the NonStop TS/MP link depth, the
link depth is limited to 255 simultaneous requests per server class, whereas the receive depth is
limited to 255 simultaneous requests per process. Therefore, even if you specify a value of 1 for
the Linkdepth command, the httpd or servlet process can simultaneously service as many requests
on that link as are specified by the value specified for the receive depth.
To increase the number of concurrent requests, you can define multiple servers in the server class
and use TANDEM_RECEIVE_DEPTH to make each server multithreaded. In this case, you can
determine the maximum number of simultaneous requests to a server class by multiplying the value
of TANDEM_RECEIVE_DEPTH by the value of Maxservers.
In the configuration file delivered with the iTP Secure WebServer, the httpd server class consists
of multiple, multithreaded servers.
Configuring the PATHMON Environment 49