SAP Web Dispatcher Workload Test

The ICM is implemented as an independent process and is started and monitored by the dispatcher. The ICM process uses a pool of worker threads to parallel process the load. This is why, if a sudden/consistent slowdown is noticed in a SAP system’s interactions with the internet, the first place administrators need to check for inconsistencies is this thread pool. The absence of adequate threads in the pool can significantly impair the ICM’s ability to uniformly distribute the request load across threads, thereby causing one/more threads be over-utilized; ultimately, this will result in a slowdown! Besides erratic thread pool usage, the sudden unavailability of the ICM and over-utilization of ICM connections can also cause disturbances in a SAP system’s internet communications. To ensure that such anomalies are promptly captured and corrected, administrators should keep an eye on the accessibility of the ICM, its thread pool usage, and availability of ICM connections. This is where the SAP Web Dispatcher Workload test helps!

This test periodically checks the availability, thread pool usage, and connection utilization of the ICM, and promptly reports the non-availability of the ICM, abnormal usage of worker threads by the ICM, and the over-utilization of ICM connections. This way, the test leads administrators to the probable causes for the breaks / slowness in the communication between the SAP system and the internet.

Note:

This test uses the Command Line program to collect the required metrics.

Target of the test : A SAP Web Dispatcher

Agent deploying the test : An internal agent

Outputs of the test : One set of results for the target SAP Web Dispatcher that is being monitored.

Configurable parameters for the test
Parameter	Description
Test period	How often should the test be executed
Host	Specify the host for which the test is to be configured.
Port	The port number at which the specified host listens. The default is 2375.
Data Collection Mode	By default, SAPCONTROL is chosen from this list indicating that the eG agent connects to the target SAP Web Dispatcher and collects the required metrics using the SAPControl web service. If you wish to collect the required metrics using the Command line program, then, choose CLI from this list. If you wish the eG agent to connect to the SAP Web Dispatcher Admin Login URL and collect the required metrics by scraping the URL, then, pick the WEBURL option from this list.
WSDL Port	This parameter appears only if SAPCONTROL option is chosen from the Data Collection Model list – i.e., if the test uses the SAPControl web service to collect measures. In this text box, specify the port number of the SAPControl web service. To determine the exact port number of the SAPControl web service, you can look up the etc/services file on the SAP Web Dispatcher being monitored. If the port number is not declared in the etc/services file, you can specify the default port number of the web service against WSDL Port If the web service is not SSL-enabled, then the default port number of the web service will be: 5<NR>13. Similarly, if the web service is SSL-enabled, then the default port number of the web service will be: 5<NR>14. <NR> in the port number refers to the system number of the SAP server being monitored. The system number is an indicator of the TCP/IP port at which the SAP Web Dispatcher server listens. For example, for a server that listens at port 3200, the system number will be ‘00’. Similarly, if the SAP server port is 3201, the system number will have to be specified as ‘01’. Accordingly, the default port number of an SSL-enabled SAPControl web service will be 50014 , if the system number is 00, or 50114, if the system number is 01.
SSL	This parameter appears only if SAPCONTROL is chosen from the Data Collection Mode list – i.e., if the test uses the SAPControl web service to collect measures. Set this flag to Yes, if the SAPControl web service is SSL-enabled. Set this flag to No, if the SAPControl web service is not SSL-enabled.
OS Username, OS Password and Confirm Password	This parameter appears only if SAPCONTROL is chosen from the Data Collection Mode list – i.e., if the test uses the SAPControl web service to collect measures. To enable the test to access the SAPControl web service and collect the required metrics, you need to configure the OS Username and OS Password parameters of the test with the credentials (i.e., name and password) of an OS user, who fulfills one of the following conditions: The name of the OS user should be declared using the service\admin_users profile parameter; (OR) The name of the user group to which the OS user belongs should be declared using the service\admin_groups profile parameter; (OR) The OS user should have the permission to execute the sapstartsrv executable Confirm the OS Password by retyping it in the Confirm Password text box.
WEB Dispatcher DIR	This parameter appears only if CLI is chosen from the Data Collection Mode list – i.e., if the test uses the command line program to collect measures. Specify the full path to the directory where the target SAP Web Dispatcher is installed. Ensure that the location specified contains the sapwebdisp and wdispmon executables.
Profile File	This parameter appears only if CLI is chosen from the Data Collection Mode list – i.e., if the test uses the command line program to collect measures. Specify the full path to the profile file with which the target SAP Web Dispatcher was started. The default name of the profile is sapwebdisp.pfl.
Timeout	This parameter appears only if CLI is chosen from the Data Collection Mode list – i.e., if the test uses the command line program to collect measures. Specify the time for which the eG agent should wait for collecting the required metrics. By default, this is 60 seconds.
Web Disp URL	This parameter appears only if the WEBURL option is chosen from the Data Collection Mode list. By default, the eG agent connects to the SAP Web Dispatcher Admin Login URL to collect the required metrics by scraping the URL. Therefore, specify the full path of the SAP Web Dispatcher Admin Login URL against this text box. For example, your specification can be: https://<SAP Web Dispatcher Host>:<SAP Web Dispatcher Port>/sap/wdisp/admin/public/default.htm.
Separate Login Page	This parameter appears only if the WEBURL option is chosen from the Data Collection Mode list. A separate login page may appear in your environment if the target SAP Web Dispatcher cannot authenticate you via HTTP authentication or if HTML FORM-based authentication is enabled or session-based authentication is enforced. By default, this flag is set to Yes indicating that a separate login page appears to access the target SAP Web Dispatcher. If your environment invokes a pop up window for login in order to access the target SAP Web Dispatcher, then, set this flag to No.
Web Disp Username, Web Disp Password and Confirm Password	This parameter appears only if the WEBURL option is chosen from the Data Collection Mode list. To enable the test to access the SAP Web Dispatcher Admin Login URL and collect the required metrics, you need to configure the Web Disp Username and Web Disp Password parameters of the test with the credentials (i.e., name and password) of a user with monitor privilege. To know more on how to create a new user, refer to Creating a New User with Monitor Privilege. Confirm the Web Disp Password by retyping it in the Confirm Password text box.

Measurements made by the test

Measurement

Description

Measurement Unit

Interpretation

Status

Indicates the current operational state of the SAP Web Dispatcher.

The values reported by this measure and their numeric equivalents are available in the table below:

Measure Value	Numeric Value
Running	1
Maintenance	2
Soft Shutdown	3

Note:

This measure reports the Measure Values listed in the table above while indicating the current operational state of the SAP Web Dispatcher. However, in the graph of this measure, this measure is indicated using only the Numeric Values listed above.

Current threads

Indicates the total number of threads created from the thread pool of the SAP Web Dispatcher for processing requests.

Number

This measure is a good indicator of the load on the SAP Web Dispatcher.

Percentage current threads

Indicates the ratio of the total number of threads created to the maximum thread setting.

Percent

An unusually heavy network load causes the web dispatcher to continue creating threads until the maximum threads setting (icm/max_threads profile parameter) is reached, i.e., the percentage approaches 100. Once the limit is reached, the requests are queued and may be dropped due to queue full or timeouts. If this high thread usage is expected, then the maximum threads setting is low. Each operating system has an upper limit on the absolute maximum number of threads that its process can spawn depending upon its kernel parameters and available stack size. Please refer to kernel parameter documentation for your OS if you want to increase the maximum threads setting beyond the default limit set by your OS.

Used connections

Indicates the number of currently open connections.

Number

The number of simultaneously open connections and their sockets can be deduced from this measure.

Percentage connections used

Indicates the percentage of currently open connections i.e., the ratio of the number of connections used to the maximum connection setting.

Percentage

Each request needs a thread and a connection for processing. If this value is consistently high, it means that there are many requests awaiting further processing. Maximum connections setting (icm/max_conn profile parameter) is further restricted by maximum sockets setting(icm/max_sockets profile parameter) which in turn is further restricted by a corresponding OS setting. The web dispatcher needs 2 sockets per connection.

Requests in queue

Indicates the number of requests that are awaiting the threads for processing.

Number

Percentage requests in queue

Indicates the ratio of the number of requests in the queue to the maximum queue setting.

Percentage

If this value is consistently high, it is possible that incoming requests are dropped due to insufficient space in the request queue. If this is expected, consider increasing the request queue size using the icm/req_queue_len profile parameter for the web dispatcher.