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Background documentation Message Server Parameters

The most important message server parameters are described below. Dynamically means that you can change the parameter while the message server is running. To display the parameters and their values in the documentation, in the message server monitor choose Goto Parameters Change.


You can also obtain information on the profile parameters using transaction RZ11. Search for parameters that start with ms/, and then choose Documentation.


This parameter specifies the host the message server is running on.

This entry must be the same on all application servers belonging to one SAP System and for this reason it should be set only in the default profile. The name of the host must be defined in the hosts file, this means for:

      UNIX: It must be entered in file /etc/hosts or on the domain name server.

      Windows: It must be entered in file C:\WINNT\SYSTEM32\DRIVERS\ETC\HOSTS or on the domain name server.


Name of the service where the message server can be reached. A default name is created from the SAP System name. This entry must be the same on all application servers belonging to one SAP System and for this reason it should be set only in the default profile.

The service must be defined in the services database.

      UNIX: It must be entered in file /etc/services or on the domain name server.

      Windows: It must be entered in file C:\WINNT\SYSTEM32\DRIVERS\ETC\SERVICES or on the domain name server.


This parameter determines the processor of an HTTP request with a URL, which points to the root directory (this is a URL without path details, for example, "/" or "/index.html"). Either the ABAP processor or the J2EE processor can be chosen to process these requests. Permitted values are abap and j2ee. The default is j2ee.


With this parameter you can control how the SAP Web AS presents the instance name externally (for example, in an HTTP session cookie). The following values are permitted:

      none: Plain text: For example: ls100_BCO_10 (default)

      md5:  MD5 hash of instance name: For example: FKOuCXKqMVOWyF5syzhQSQ

If you use this parameter, make sure it is set the same on all SAP Web AS instances and in the message server (preferably in the default profile only), so that all application servers use the same instance name and the message server also observes the parameter. Only then can HTTP load balancing work. 


If you use SAP Web Dispatcher for load balancing, keep in mind that the parameter does not have to be set in the profile of the SAP Web Dispatcher.


This parameter is used for logging. You can use this parameter if you detect problems of a sporadic nature with the message server, and cannot increase the message server trace level because the file would become too large. If this parameter is set accordingly, logons to and logoffs from the message server are also logged with trace level 1.

This is a bit mask (2 bits); the following values are allowed:


No logging


Logons to and logoffs from application servers are logged


Activate and suspend clients are also logged; this means the temporary suspending of a client when it sends more date than can be received.

Default: 0

Dynamic: yes


Short description of the SAP system. This description is transferred to the domain server when the connection is established. It is displayed there in the list of systems.                                    

Default: message server $(SAPSYSTEMNAME)

Dynamic: yes


Determines the timeout value for the calls NiRead (read from network) and NiWrite (write to network) in milliseconds. If within this time interval not all the data has been sent or received, the action concerned is interrupted and later reinitiated.                

Default: 5000

Dynamic: yes


You log on the message server in two steps.

      Establish a connection to the message server

      Logon to the message server                                        

The connection is broken if you do not log on to the message server within a specified time after establishing the connection.          

Value 0 deactivates this check.                      

Default: 300 (seconds)

Dynamic: yes


This parameter identifies the message server port where HTTP(S) requests can arrive at.

The syntax is the same as for parameter icm/server_port_<xx>, with the following exceptions:

      Options KEEPALIVE, VCLIENT and TIMEOUT are ignored.

      Only HTTP and HTTPS protocols are accepted - an error message is generated for any other protocol.


The parameter replaces the parameters ms/http_port and ms/https_port used earlier. Do not use these any longer for the message server. These parameters are only needed by the SAP Web Dispatcher.


Maximum buffer size of an HTTP or HTTPS request. The buffer is allocated by the message server dynamically and released once the request has been processed.

Default: 65536 bytes

Dynamic: yes


If the parameter is set to 1, the message server uses the domain name, with which the client logged on to the message server, for the REDIRECT request. If the parameter has the value 0, the domain that the dispatcher communicated to the message server is used.

Default: 1

Dynamic: yes


This parameter is used to control HTTP requests and can have the following values:

      1 : HTTP request handlers in ICF are to be called

      0 : HTTP request handlers in ICF are not to be called

The message server calls a few HTTP request handlers in the ICF, to fetch information about HTTP load balancing and distribution of HTTP requests. To do this it sends the URL that contains default_host/sap/public/icf_info/urlprefix or logon_groups to an application server.

If there is no HTTP request handler available or it has an error, this handler is flagged as incorrect. If this HTTP request handler is to be called again later, this parameter must be set dynamically to 1.

Default: 1

Dynamic: yes

ms/http_logging and ms/HTTP/logging_<xx>

This parameter controls the HTTP Logging


This parameter specifies which methods are used to search for SAP-specific parameters in the HTTP request. The following values are permitted:

      1: Only the URL is searched.

      2: First the URL is searched, then the form specification.

      3: The URL is searched, then the form specification, and then the cookie.

The search is done according to SAP specifications.

      sap-trace: To activate the trace for this request, the trace results are written to the trace file on the message server (dev_ms).

      sap-group: Load balancing using the SAP logon groups


Number of HTTP or HTTPS clients that can connect in parallel to the message server.

Default: 500

Dynamic: no


Number of ports on which the message server can receive HTTP and HTTPS connections.

The number of virtual hosts is determined by this parameter.

The total number of HTTP, HTTPS, and virtual hosts must not exceed this value.

These are defined in parameters ms/server_port_<xx>.

Default: 20

Dynamic: no


If the data cannot be read to or written from the network within the specified time span (seconds), the connection to the HTTP or HTTPS client is closed.

Default: 20

Dynamic: yes


If a request is to be forwarded to a J2EE server, you can set in this parameter, that only those servers that also contain the ABAP engine are selected.

To do this set the parameter to 1.

Default: 0

Dynamic: yes


Specifies the maximum time in seconds before the message server checks inactive connections. A data packet is sent to the client for the check.                              

Value 0 deactivates this check.                    

Default: 300

Dynamic: yes


Number of clients that can log on to the message server at the same time.

Default: 300

Dynamic: no


Number of open requests that can be administered in the message server at the same time.

Default: 10000

Dynamic: no


Specifies the maximum amount of time in seconds the message server waits for a request.                                     

Default: 20

Dynamic: yes


The parameter specifies the maximum number of virtual hosts that the message server can open.

One virtual host can be assigned to each HTTP or HTTPS port (add VHOSTIDX to ms/server_port_<xx>).

As soon as an HTTP request is directed via an HTTP or HTTPS port to the message server, only those application servers that have likewise opened a virtual host with this index are included in the load distribution.

Dynamic changes of this parameter affect only those application servers that have logged on to the message server after the change was made.

The total number of HTTP, HTTPS, and virtual hosts must not exceed the total number of ports (ms/http_max_ports).

Default: 16

Dynamic: yes


Activates or deactivates the tracing of incoming and outgoing network connections. The following values are permitted:

      0 = Trace is deactivated

      1 = Trace is activated

Trace Parameter rdisp/TRACE*

For a description of this parameter see Trace Logging.




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