Logon
Groups:
Logon groups (or work groups)
are configured to dynamically distribute the load being processed by the dialog
work processes.
In many cases, SAP systems
will have 2 or more sap abap instances. In these cases, logon groups can be
configured to achieve dynamic distribution of dialog users on the ABAP
instances.
A report runs in SAP every
5minutes which determines the load across each server and updates in the memory
area of the message server.
Other criteria:
Logon groups according to SAP
application / module: Separate logon groups can be setup for
applications/modules such as HR, FI/CO, SD, MM etc. It means HR module users
will be restricted to logon to identified instances, similarly other module
users are allowed to login to their respective identified instances. The
advantages of this method, is only the programs of the respective module are
loaded into the program buffer of the particular instances of that logon group.
Due to this, program buffer requires less memory and this helps to avoid buffer
displacements thus improving system performance.
Logon groups according to
language, country or company division:
If your SAP system is
operating across multiple countries or languages, in that case it is good idea
to create logon groups specific to a country or language. By this way the data
and text related to specific country or language will be loaded into the buffers
of the respective instances.
This minimizes buffer
displacements and improves system performance. Also less memory is required for
the table buffer.
Logon
groups for certain user groups:
i) We can setup separate logon
groups for some department like sales whose work is performance critical. For
that logon groups we assign instances which operates with high level of
performance (e.g: high speed processors, less users per server, no background
or update workprocesses configured or a dedicated network etc)
ii) Some department users may
take time-consuming reports in dialog mode. For these type of users, you may
have to create separate logon group and assign an sap instance where profile
parameter rdisp/max_wprun_time is set to very high
In this way we can separate performance
critical/resource intensive applications from others.
Logon
groups for the SAP Web Dispatcher:
For direct ABAP web service requests, we
can setup logon groups that the SAP Web Dispatcher can use. If logon groups are
not configured for web dispatcher, the load is distributed to all ABAP
instances on which ICM is configured. Also, based on URLs we can
distribute certain group of requests to dedicated logon groups.
Logon
groups for ALE/RFC:
Asynchronous RFCs are used to process in
parallel. However if the parallel processes are not limited properly, they can
occupy all the available processes which impacts dialog users and can bring
down the application. So, it is good idea to create separate logon groups for
incoming RFC calls so that RFCs are kept separate from workprocesses of online
users and thus avoids impact to dialog users.
Guide
lines:
After
assigning instances to logon groups
i) We need to verify whether the
instances of logon groups are evenly distributed or not.
ii) If an instance hangs or
temporarily got disconnected, you should be able to redistribute the users
So, you need to setup at least 2 sap instances
for each logon group.
iii) Setting up logon groups
involves extra administration and monitoring. So, unnecessarily large number of
logon groups shouldn’t be setup
How to
setup logon groups?
SMLG transaction code is used for creating logon
groups.
Logon to
SAP system and goto SMLG transaction as shown below:
In the
above example there are 2 instances (00 and 09) in this SAP system. These are
not yet assigned to any logon group.
We can
create a new logon group by clicking on highlighted create icon on the above
screen. It results in below screen.
In the above screen, either select logon group
from dropdown or provide its name if you are newly creating. After that assign
instance for that logon group and click on copy to save the assignment.
In this example iam creating two logon groups
hr and fico and assigning instances 00 and 09 respectively. Please find below
screenshots which explains the same.
Repeat
the same step and create logon group fico and assign instance 09 for it as
shown above.
After
doing this, you can see following logon groups in SMLG
Once you
are done with logon group setup, please log off from SAP system and goto SAPGUI
of the respective SAP system.
Click on
properties of the respective GUI entry and goto to connection tab as shown
below.
Please select Group/Server selection option
from the drop down of Connection Type as shown above and maintain description
and system id of the instance as shown above.
Now, you
should be able to view the newly created logon groups as shown in below figure:
Also,
please note you are able to view logon group SPACE also which gets created by
default
Now, you
can configure any desired logon group to the users as shown below:
For
example in the above screen fico group is assigned to the end users in his GUI
so that now onwards, he will login into instance number 09 only.
No comments:
Post a Comment