NW 7.0 WebAS Java Built-In functionality for Load Balancing?

[Former Member]

Hi folks!

I've studied SDN, SMP and SAP Help again and again, but found no clear statement on this: Has the NW 7.0 WebAS Java any built-in functionality to achieve Load Balancing in a multiple instance Web AS Java system?

The ABAP stack has the ABAP Message Server. The Java stack has a Message Server, too, but obviously without the functionality of Load Balancing.

That is: Do I really need a SAP Web Dispatcher or other External Load Balancer to achieve Load Balancing?

The concrete system is a BI 7.0 ABAP and Java Double Stack Installation with an additional Dialog Instance for ABAP and Java. ABAP Web Requests are successfully load balanced using the ABAP Message Server Port 8120. But what about Java Web Requests (coming with new BI 7.0 features).

Thanx for any hint in advance.

Regards,

Volker

[Former Member]

Hi Volker,

Sounds like you are on the right track.

Yes, 7.0 requires web dispatcher for http dispatching to the java or abap engine. The nice thing, if it is a single or dual stack system is that 1 web dispatcher can dispatch to both/either. If you have 2 different SIDS, ie JL0 for java and AL0 for abap, then you have to have 2 seperate web dispatchers with a seperate URL for each.

The message servers, as you suggest, only load balance accross processes within the same instance. If you need to load balance accross several instances/app servers, then you must use a web dispatcher.

Hardware load balancers can also do this and have some advantages but also some drawbacks. HW LBs often provide much more sophisticated LB algorithms but they also lack some of the intelligence provided with the app integration privided by SAP WD. Also, if volume is going to be an issue, then a HW LB is the way to go. SAP WD has definite volume limitations (you will have to benchmark to see for your particular usage scenario) especially if HTTPS is present in your envionment. Often times HW LBs also have extra benefits like caching and/or compression features which can dramatically boost the user experience.

Let me know what other questions you might have.

jwise

[Former Member]

Hi Joshua!

Thanx for ASAP and clear reply. And you are really sure that Java Message Server does no LB?

I'm asking once again, because the ABAP Message Server in NW 7.0 still can be used to load balance RFC-, SAPGUI and HTTP(S) Requests ... and it works fine in our heavily used ERP environment.

Thanx a lot for double-checking this important question.

Regards,

Volker