Operating the SAP Web Dispatcher (SAP Library - Architecture of the SAP Web Application Server)

Operating the SAP Web Dispatcher

Use

The following information describes how you start and stop the SAP Web dispatcher, and the prerequisites that your system must meet to enable you to use the SAP Web dispatcher.

SAP Web Dispatcher describes how you use the SAP Web dispatcher.

Prerequisites

The prerequisites for operating the SAP Web dispatcher are:

SAP Web AS 6.20 with a 6.20 kernel

The HTTP port for the SAP message server is configured (profile parameter ms/http_port)

There is a profile file for the SAP Web dispatcher (see Example: Profile File of a SAP Web Dispatcher and Profile Parameters of the SAP Web Dispatcher)

The SAP Web dispatcher must be able to contact the HTTP port of the SAP message server.

The following services must be activated in the HTTP service tree (Transaction SICF):

/sap/public/icman

/sap/public/icf_info/*

Procedure

Starting the SAP Web Dispatcher

You start the SAP Web dispatcher with the command

sapwebdisp pf=<profile name> [-f <tracefile> -t <tracelevel> -cleanup -shm_attch_mode <mode> -auto_restart -version]

The optional parameters have the following meaning.

You can use -f to determine the name of the trace file. The standard is dev_webdisp.

You can use option -t to set the trace level.

-cleanup means that common resources (shared memory and so on) are released. This is necessary if the SAP Web dispatcher ran was not stopped in an orderly manner the last time it ran, but was terminated by a crash.

-shm_attch_mode <mode> determines what should happen to the shared memory of the SAP Web Dispatcher. Here, <mode> is a number that is a combination of the following values (bit mask):

1: Delete the shared memory of the SAP Web dispatcher (cleanup)

2: Try to connect to the shared memory (attach)

4: Create a new shared memory (create)

This results in the following possible options:

1: The shared memory is cleaned up and the SAP Web dispatcher ends. The behavior is the same as with the option of –cleanup.

2: The SAP Web dispatcher connects to the existing shared memory (attach). If this does not exist, the SAP Web dispatcher ends with an error.

3: Not useful

4: The SAP Web dispatcher creates a new shared memory. If this exists already, the SAP Web dispatcher ends with an error. This is also the default value, that is, the SAP Web dispatcher behaves in this way if the options -shm_attch_mode <mode> and -cleanup are not used.

5: If a shared memory exists already, it is deleted. A new shared memory is then created.

6: The system tries to attach it to an existing shared memory. If a shared memory does not exist, a new one is created.

7: As 5

Note

These settings are useful for managing SSL client IP addresses. With the appropriate settings, this information does not get lost in the SHM, but can be reused if the SAP Web dispatcher crashes. See also SAP Web Dispatcher and SSL.

-auto_restart: With this option you can make the SAP Web dispatcher highly available at process level. The process is described in the section High Availability of the SAP Web Dispatcher.

-version displays the version of the SAP Web dispatcher. The program is not started.

Example

You usually start the SAP Web dispatcher as follows:

sapwebdisp pf=<Profile name>

Stopping the SAP Web Dispatcher

If you want to stop the SAP Web dispatcher, you determine the parameter ID and enter the following command: kill -2 <pid> (UNIX) or sapntkill -2 <pid> (Windows NT).

Recommendation

You can take the PID of the SAP Web dispatcher from the trace file dev_webdisp in the work directory.

Result

You start or stop the SAP Web dispatcher.