Even logon distribution using load balancing

[Former Member]

We are trying to scale our system to distribute logons across multiple app servers. We have setup Logon groups and have set MSHOST in our connection configurations but since all logon's occur at roughly the same time, they all end up going to the same app server. We have 40 connections and ideally would want 20 to go to server A and 20 to go to server B, so that when each logon has work to do, the load gets evenly distributed.

We have tried modifying the threshold value for each app server in the logon group but that has had no impact.

Any suggestions?

Thanks

Tim

[anindya_bose · Accepted solution]

Tim

Logon group should work fine if there is difference in login time by at least 5 minutes.

SAP calculates the best server for dialog logon by determining the quality of a particular server. It gives weightage to number of users and response time of dialog in a ratio 5:1 and then calculates the quality of the server. This information gets updated in every 5 mins. User at a particular time are assigned to the best server ( according to quality).

When all the users are moving to the same server, you can check what is the quality of a particular server.

SMLG-->F5 ( Goto>Load Distribution) and SMLG--->F6(Message server status area). Check if the current logon instance is changing with time. If that is changing then your logon groups working...If not then then raise a OSS message to SAP.

Even if your logon grp working but you are unable to get the advantage,

you can set up multiple logon group with different app server. Like GRP1 will have App1, APP2 then GRP2 will have App3, App4 and so on and then ask your user to use different logon grp.

One more thing, what is the auto_logout setting is your system? if users frequently login and then after work log off they can get the best effor in terms of logon group.

Waiting for further details from you

Edited by: Anindya Bose on Aug 11, 2009 10:44 AM

[thomas_valentini]

Hi Tim,

have a look at SAP note 51789 - this works like a charm for nearly 50/50 distribution.

Best regards

Thomas

[Former Member]

Thanks for the suggestion. One of the things I neglected to point out was that these are RFC logons. Further searching the SAP portal, turned up note 593058 which describes how to get round robin distribution for rfc logons. However, this doesn't seem to be working for us - we get all of our logons still going to the same app server. I am presuming that the random behavior was brought forward to the 7.0 rfcsdk.

Has anyone had any success getting this approach to work?

Thanks

Tim

[anindya_bose]

Tim

from RZLLICLASS table you can change the FAVTYPE to B ( i.e best server) . you can also change TIMERERD to some lower value ( may be 120 if already more than that).

But one question here...to use RFC load balancing the servers ( other SAP systems) which are using your system need to enable that in their RFC connection. Are you sure they are using RFC connection with Load Balancing facility when calling your server? Please check with their SM59 config.

[Former Member]

We have an external application that is connecting. It has the right settings for MSHOST, R3NAME and GROUP. Is there something else that we should be setting? Type B is not relevant since the underlying code is using RfcOpenEx.

Tim

[anindya_bose]

OSS note

https://service.sap.com/sap/support/notes/1158425

https://service.sap.com/sap/support/notes/986373

could be of help. if you havent checked yet.....