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Use

SAP Web dispatcher needs information about the capacity of a server in order to balance its workload in relation to the other servers.

Each application server has a capacity value for each of the services it provides (ABAP, Java). You can display these values from the Web Interface of the message server. The number following DIA= or LB= is the capacity value for ABAP or Java. In In ABAP the number refers to the number of configured dialog work processes; in Java the number refers to the number of configured server nodes.

The Web dispatcher takes the maximum value of both values as the standard capacity setting for this application server. If the server provides only ABAP or only Java, the Web dispatcher uses the respective capacity of each.

Note

The capacity is used as an estimated value of the actual “power” of an application server. Depending on the application, the CPU number, tact frequency, cache sizes, or other properties are important here. As it is safe to assume that more dialog processes and server nodes are configured on more powerful machines, this number can be seen as an approximate benchmark. The “virtual load” (load factor) is based on this static estimated value and is therefore also only a rough indicator.

With a high workload the dynamic elements of load balancing (ping times, current number of open requests, and so on) indicate precisely what the actual load is, and therefore the static capacity value is not important.

You can see what capacity of SAP Web Dispatcher is used for load balancing in the Web Administration interface under Monitor Server Groups in column Capacity. Here you can also overwrite the capacity value with the right mouse button. The changes are lost when the SAP Web dispatcher is restarted.

You can overwrite the capacity value permanently by setting the profile parameter wdisp/server_ <xx> in the SAP Web dispatcher profile. It has the following syntax: 

wdisp/server_<xx>= NAME=<name>, [LBA=<ABAP_capacity> | LBJ=<Java_capacity>], ACTIVE=<0|1>

The options have the following meaning:

  • <name>: name of the instance (not of the host)

  • Capacity values for ABAP and Java are different. The ABAP capacity is specified in option LBA, Java capacity in LBJ. So with a dual-stack instance, you can specify these capacities separately (see example below).

  • The ACTIVE option specifies whether the application server takes part in load balancing or not. If ACTIVE=0, the server does not get any requests at all. If the option is not set, the standard setting is for the server to take part in load balancing.

  • <xx> are numbers is ascending order.

Example

wdisp/server_0 = NAME=binmain_BIN_53, LBA=23

wdisp/server_1 = NAME=binmain_BIN_53, LBJ=12

wdisp/server_2 = NAME=myserv_1, LBA=11

Caution

Normally, the capacity set by the system based on information from the message server is ideal for operation.

You should only overwrite the capacity set by the system if you have identified weaknesses during productive operation that you want to correct.

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