RFC: Multiple Hosts, same Program ID

[Former Member]

Hello,

is it possible to create a single RFC-Connection (sm59, TCP/IP, registered Program ID ABC) and then connect with multiple hosts with the same program ID to this single entry? Indeed it seems to be possible, but I didn't found any docoumentation which describes it as supported or not supported.

We want to connect some instances of a non-SAP System to our R/3 (Web AS 620), but for different reasons, we want this connection to be transparent for SAP. So SAP shouldn't care if one, two or n systems are connected.

Any suggestions/tipps?

Regards

Markus

[Former Member · Accepted solution]

Hi Markus,

Yes, it is possible and the SAP system will balance the calls on the different external systems with a round robin algorithm.

It means also that the SAP system does not know in advance on which external system the call will be done and that all the remote functions should exist in all external systems.

You can experiment this with the standard RFC server program rfcexec.exe.

On a PC, open 2 DOS boxes and launch rfcexec.exe in each to register in the same SAP system.

When you call, function RFC_REMOTE_EXEC for example several times on the same SM59 destination, you will see the calls switching between the 2 DOS boxes.

I hope this is clear !

Regards,

Olivier

[Former Member · Accepted solution]

Hi Olivier,

this sounds great. This is the behaviour we hoped for so we don't have to handle multiple rfc connections and load-balancing on our own.

Do you know where this is documented? I couldn't find it yet @help.sap.com

Thank you

Markus

[Former Member · Accepted solution]

Hi again Markus,

Sorry but I experienced this behaviour years ago and I don't remember where I got the information. It must have been in an OSS note...

The behaviour is great for load balancing, but do remember this not a high availability set up.

If one of your RFC servers crashes, the registration will still be in the SAP gateway memory and the SAP system will sill try to send calls to a crashed RFC server.

If you have 2 RFC servers, 1 call from 2 will fail...

Regards,

Olivier

[Former Member · Accepted solution]

Hi Olivier,

for getting you right, I'll create the following scenario

• serverA registeres on SAPsystemX with program ID ABC

• serverB registeres on SAPsystemX with program ID ABC

• SAPsystemX sends his calls to program ID ABC and the calls are automaticall load-balanced between serverA and serverB

Now, assuming that serverB crashes, SAPsystemX doesn't recognize this and still sends calls to serverA and serverB?

If this is the point, this would really slow down my enthusiasm, if there's now workaround

Thank you

Markus

[Former Member · Accepted solution]

Markus,

Yes, your scenario is exactly what I wanted to warn you about.

I tried it for the last time years ago.

I would advice you to redo the test to see if this has been improved.

Sorry to slow down your enthusiasm, nothing is perfect !

Olivier

[Former Member · Accepted solution]

Hi Olivier,

ok, thank you very much for your help.

I'll do some testing, perhaps the behaviour changed over the years.

Anyway I'll appreciate any further hint, if someone also has tried this before or even knows if this is an official feature or just as-is.

Best Regards

Markus