logon groups.

[debashree dutta]

USE:

we define logon groups to determine how client requests to certain applications are load balanced when our system setup uses the SAP Web Dispatcher or a third-party hardware load balancer in front of our application servers. For example, we can define a logon group so that a certain application (such as one with high CPU usage) is accessible only on two instances within our cluster, which are running on machines equipped with extra CPU resources.

Features:

When we use logon groups for load balancing, then the logon group the application is requested which must be present in the request URL. It is presented next to the application alias of the requested application (separated by the zone separator symbol that is configured). The zone separator is configured in the HTTP Provider Service using the Visual Administrator as described in Configuring the Zone Separator.



To request an application called TestApp within the test logon group (provided the default zone separator is used), we can use the following URL: http://<host>:<port>/TestApp~test/<application_resource>.

The logon group definition consists of the following actions:

· Definition of the instance IDs of the Java instances in the cluster where applications from this group are accessible.

· Definition of the application aliasesof the applications that are requested with the corresponding logon group.

*************************************************************Creating a Logon Group or Adding an Instance to a Logon Group
...

1. Choose CCMS->Configuration ->Logon Groups, or call transaction SMLG.

2. Choose (Create Assignment), and specify the desired name of the logon group in the Logon Group input field. Enter the name of the desired Instance that is to belong to the logon group.



The logon group SPACE is reserved for SAP; therefore, do not use this name.

3. Repeat the last step until you have entered all instances that are to belong to the logon group.

4. Save your changes.

*************************************************************
Deleting a Logon Group or Removing an Instance from a Logon Group
...

1. Choose CCMS->Configuration-> Logon Groups, or call transaction SMLG.

2. Select any assignment for the logon group that you want to delete or from which you want to remove an instance.

3. To remove an instance from the selected logon group, choose Remove Instance, enter the desired instance on the next screen, and confirm your choice by choosing (Delete).

4. To delete the desired logon group, choose Delete Group and confirm your choice by choosing (Delete) on the next screen.

5. Save your changes.
*************************************************************
Changing Properties of an Assignment, a Logon Group, or an Instance
...

1. Choose CCMS->Configuration->Logon Groups, or call transaction SMLG.

2. To change the properties of an assignment, double-click the assignment, and switch to the Properties tab page.

3. You can change the following properties:

○ IP address of the application server

Only enter a value in this field if the application server associated with the instance needs to be addressed by the front end with a different IP address to the one used for application server-internal communication. This value applies only for the selected assignment.

○ Settings for external RFC call

You can use this indicator to determine whether logon using an external RFC connection is to be permitted. This value applies to the selected logon group.

○ Threshold values for dialog response time and number of users logged on

If you log on using a logon group, the logon is automatically performed using the instance of the group that currently has the best dialog quality. This quality is a key figure that is calculated from the number of users logged on and the average dialog response time. To allow the different prerequisites of different instance to be taken into account in this calculation, you can set threshold values for the dialog response time and the number of users yourself. The larger the actual values for response time and the number of users are in comparison to the threshold values set, the lower the quality. These figures apply for the selected instance.



The values for Response Time and Users are not absolute limits, but rather thresholds. Even if the current value for response time or number of users is higher than this threshold value, it is possible to log on to another instance. The threshold values only influence the calculation of the current logon server of the logon groups.



You can use a preview to see how the settings of the threshold values can affect the quality calculation, based on the current performance data. Choose Test to do this. In a logon group, the instance with the highest quality key figure is always selected for the logon.

4. Choose Copy, and save your changes.

[Rajnikanth]

Nice post





Regards
Rajnikanth

[dutta]

very good to see a post on this topic

[hussaini]

good information Debashree

nice work

keep it up