Learn about Message Server in SAP

• Communication Channel between Application server/instances
• Load Distributions of logon
• Information point for application server

Monitoring and Administration of the SAP Message Server

The SAP message server runs as a separate process, mostly on the same host as the central instance. If an SCS instance (SAP Central Services) or ASCS instance (ABAP SCS) is configured in the system, the message server is part of this instance.

Only one message server can run in each SAP system. It performs the following tasks in the SAP system:

1. Central communication channel between the individual application servers (instances) of the system
2. Load distribution of logons using SAP GUI and RFC with logon groups
3. Information point for the Web Dispatcher and the application servers (each application server of the system firsts logs on to the message server)

When an instance is started, the dispatcher process contacts the message server so that it can announce the services it provides (DIA, BTC, SPO, UPD, and so on). If the connection setup to the message server fails, an entry is made in the system log (syslog).

If the message server stops working, it must be restarted as quickly as possible to ensure that the system continues to operate smoothly.

The following section explains how to administrate, test, and monitor the message server.

Prerequisites

To monitor the message server at operating system level, your require access to the host on which the message server is running. You can log on here with the <sid>adm user.

Process

You have different options for monitoring and testing the message server:

Monitor the Message Server in the SAP System

To monitor the message server, you can use the message server monitor (transaction SMMS) in the SAP system. You can check and change all the important settings, create and view trace files, read statistics, and so on.

Monitor the Message Server from the Browser

You can display details of the servers and logon groups from the Web browser too. To do this, use the host of the message server and the HTTP port of the message server (ms/server_port<xx> profile parameter) in the URL.

Monitoring and Testing the Message Server at Operating System Level

At operating system level there are various programs available that are delivered with the standard system.

You can normally find the test programs in the /usr/sap/<SID>/SYS/exe/run executable directory.

The msmon monitoring program provides the same functions as transaction SMMS in the SAP system.

You can use the lgtst test program to check the connection to the message server and to display the active instances and logon groups that the message server can currently see.

You can use the msprot program to monitor the message server. The program continuously issues the status of the application servers logged on the message server and is stopped if the message server is stopped. You will be notified of the termination of the message server and can respond to this.

Security Settings for the Message Server

You can make communication to the message server more secure by setting a few profile parameters.