SAP Web Dispatcher Cache Test

The SAP Web dispatcher can be configured in such a way that the contents (static and dynamic) are stored in the cache, and the next request to this page can be satisfied quickly from the cache. The SAP Web dispatcher normally forwards incoming requests to an Internet Communication Manager (ICM), which is responsible for Web requests in SAP NetWeaver AS. The advantage of caching in the Web dispatcher over caching in the ICM is that the cache is located at the initial access point where all the requests arrive, and therefore all backend servers activated later and their network connections are offloaded. Caching is deactivated in the SAP Web Dispatcher by default. You need to activate caching by specifying a URL prefix and cache directory in the parameter icm/HTTP/server_cache_0 in the Web Dispatcher profile with which the SAP Web Dispatcher was started.

This test monitors the cache of the SAP Web Dispatcher and reports the total size of all cache entries, the total number of cache entries etc. Using this test, administrators can easily detect the number of invalid entries and remove them from the cache. This way, administrators can analyze how quickly the cache processes the requests. In the process, the test points to poor cache usage and processing bottlenecks, and reveals if the cache is poorly sized.

Target of the test : A SAP Web Dispatcher

Agent deploying the test : An internal/remote agent

Outputs of the test : One set of results for the SAP Web Dispatcher 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, this flag is set to Sapcontrol indicating that the eG agent connects to the target SAP Web Dispatcher and collects the required metrics using the SAPControl web service. However, if you wish to collect the required metrics using the Command line program, then, you can set this flag to CLI.
WSDL Port	This parameter appears only if the Data Collection Mode flag is set to Sapcontrol – 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 the Data Collection Mode flag is set to Sapcontrol – 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 the Data Collection Mode flag is set to Sapcontrol – 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 the Data Collection Mode flag is set to CLI – 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 the Data Collection Mode flag is set to CLI – 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 the Data Collection Mode flag is set to CLI – 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
Detailed Diagnosis	To make diagnosis more efficient and accurate, the eG Enterprise embeds an optional detailed diagnostic capability. With this capability, the eG agents can be configured to run detailed, more elaborate tests as and when specific problems are detected. To enable the detailed diagnosis capability of this test for a particular server, choose the On option. To disable the capability, click on the Off option. The option to selectively enable/disable the detailed diagnosis capability will be available only if the following conditions are fulfilled: The eG manager license should allow the detailed diagnosis capability Both the normal and abnormal frequencies configured for the detailed diagnosis measures should not be 0.

Measurements made by the test
Measurement	Description	Measurement Unit	Interpretation
Total entries	Indicates the total number of entries in the cache.	Number	A high value is desired for this measure.
Invalid entries	Indicates the number of expired or invalidated entries in the cache.	Number	If there are too many invalid entries, it indicates that the cache has become stale. If the value of this measure is gradually increasing, then it indicates that the cache is not sized adequately. The appropriate cache needs to be resized using the icm/HTTP/server_cache_<x>/max_entries and icm/HTTP/server_cache_<xx>/size_MB parameters
Percentage invalid entries	Indicates the percentage of expired or invalidated entries in the cache.	Percent	This measure is the ratio of the Invalid entries to Total entries measure. A low value is desired for this measure.
Size	Indicates the total size of all cache entries in the cache.	KB