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Load balancing Java instances with EP

Former Member
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Hi all,

I am wondering if EP provides load balancing when connecting to backend java systems. For example, when a user connects to the enterprise portal and then, through portal, connects to a java system like BI portal or Biller Direct, are they being load balanced? From what I have read, it sounds like the portal connects to the message server to load balance these backend systems, however I have heard some concerns that a web dispatcher instance may be needed for each backend java system. Is this true or is the load balancing functionality provided by the portal sufficient?

Our users will only be connecting to these systems via enterprise portal. We are planning to install a web dispatcher instance to balance the portal users but I am trying to figure out if more instances are needed to balance the other java systems.

I have read the help.sap.com documentation on webdispatcher, as well as these two notes, but none directly addresses this question. Experts, I would really appreciate your help!

Note 1040325 - HTTP load balancing: Message Server or Web Dispatcher?

Note 649008 - HTTP load balancing using the SAP message server

Thanks,

Michelle

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Answers (2)

Answers (2)

Former Member
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Hi Michelle,

You can go through this link which might help you in understanding various scenarios in Load balancing with EP:

http://help.sap.com/saphelp_nw04/helpdata/en/b5/e8239ef7bd494f896a84625d4b688f/content.htm

Hope it helps.Do award points if found helpful.

Regards,

Gourav.

benjamin_houttuin
Active Contributor
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Michael,

If I understand you right then the Enterprise portal you are talking about is your "super/main/consumer" portal and you ahfe other portals and java systems as producers?

If a java installations have one or more Dialog Instances then I would advice you to also install Webdispatchers for those systems too.

But If these java installations only hava a CI then you don't need webdispatcher as the dispatcher in the instance will load balance on the server nodes.

Instead of a webdispatcher you could also use a hardware solution but webdispatcher will suit your needs I guess.

Following ASCII art figure hopefully makes it a litle bit clear:


                                   1. Webdispatcher
                                          |               
                      2. Enterprise Portal CI + DI etc etc
                                          |         
          ------------------------------------------------------------------------------
          |                                      |                                     |
3a. Webdispatcher                       3b. Webdispatcher                              |
          |                                      |                                     |            
4a. BI Portal CI + DI etc etc           4b. XYZ Portal CI + DI etc etc         4c. Java instance CI only
         |                                       |                                     
5a. BI ABAP system                      5b. XYZ ABAP system                   

Good Luck,

Benjamin Houttuin

Former Member
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Thanks for the helpful information. That clears things up for our BI producer portal, but I still have a question about some other systems.

For an ABAPJAVA system like TM, which doesn't have a producer portal, but does have an abapjava dialog instance, do we need a web dispatcher to balance users coming in through EP?

Former Member
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Hi ,

Webdispatcher main objective is loadbalancing.If you want implement load balance if you have morethan one dailogue instance, you can implement loadbalancing using webdispatcher

Koti Reddy

Close the thread If your issue resolved.

benjamin_houttuin
Active Contributor
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>

> Thanks for the helpful information. That clears things up for our BI producer portal, but I still have a question about some other systems.

>

> For an ABAPJAVA system like TM, which doesn't have a producer portal, but does have an abapjava dialog instance, do we need a web dispatcher to balance users coming in through EP?

Yes, you can treat Dual stacks in this the same as Stand alone Java regarding WebDispatcher

Former Member
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What is the technical explanation? Why can't the message server be used to load balance the users coming in through EP?

benjamin_houttuin
Active Contributor
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Hi,

It can, if you connect to the http port of the message server then it will do a redirect (dispatch) to the availible Instance.

Only thing is that the url will realy change.

http://help.sap.com/saphelp_nw70/helpdata/EN/43/a95d83e27417b9e10000000a1553f6/frameset.htm

For example you have a CI on Server1.domain.org and a DI on Server2.domain.org and another DI on Server3.domain.org

Then when browsing to the Message Server port on Server1 then it will do a "hard" redirect to one of the instances.

So you will actualy see a url change going on in your browser... Thats not so cool as End-Users might store the url in there favorites.

Then from then on they will only contact this instance only...

So althoug using the message server like described above will technically do a sort of loadbalance I would realy use the SAP Webdispatcher if I where you as it is more suitable...

If you might think that you need an additional server for it and if that is withholding you than I can say from experience that with my current customer we run the Webdispatcher on the CI and its working perfect...

Cheers,

Benjamin Houttuin

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Hi,

This is not necessarily correct. For HTTP load balancing issues I ALWAYS recommend using the webdisp. Please check the link below:-

http://help.sap.com/SAPHELP_NWPI71/helpdata/EN/28/75153a1a5b4c2de10000000a114084/frameset.htm

Which states:-

SAP recommends that you use the SAP Web Dispatcher as the entrance point for your Web queries. This is then used as the access point for your network and also executes load balancing for HTTP requests.

More information: SAP Note 1040325.

You can use HTTP load balancing on the SAP Message Server for stateless applications only. For stateful Web applications with a state in the back end (such as BSP applications), you require the Web Dispatcher.

You can only use the SAP message server for HTTP load distribution if the browser is the direct client of the message server. If another component lies between the client (browser) and the message server, (for example, the portal), you cannot use the message server to distribute the load.

Michael

Edited by: Michael Mulvey on Oct 23, 2008 3:52 PM