Guidelines for making a decision about using Java-only system instead of double-stack
- Lower operational cost from easier maintenance (1 hr install time and 90 sec restart time)
- Only half of hardware requirements compared to double stack deployment
- 60% less energy consumption
- AEX cannot use the WS adapter. As WS is an ABAP adapter
- ccBPM is not available for AEX
- ABAP mapping cannot used by AEX ABAP mapping is executed in ABAP, therefore cannot be used by AEX
In addition, I want to notice that SAP plans to provide and invest into migration support from dual stack to single stack in future. (p.35)
In conclusion, wanna say that due to leaner hardware requirement and performance improvements, AEX became very attractive as an installation option.
In spite of, SAP AG heavily invested into Java platform, there are still certain limitations from customer point of view which must be taken into consideration before going for this option.
If it’s a new implementation and a customer absolutely sure that there will be no scenarios related to the limitations on Java stack (WS adapter, ccBPM, ABAP mapping)the best option is to embark on Single stack because its loose coupling, highly available, dynamic routing(content based) possible, message blacklisting,lower TCO, faster installation and restarting and of course better performance and throughput. Then definitely go for this option.
If you know that some system-centric or human-centric complex scenarios are required and ccBPM could help, you can still go for Java only stack composed of SAP NW Process Orchestration (PO).
SAP PO is a combination of a bundled product of PI, BPM and BRM. (more information on http://scn.sap.com/community/pi-and-soa-middleware )
Although, ccBPM and BPM are based on different notations, BPEL and BPMN respectively, you can use NetWeaver BPM for System-to-System Message Orchestration (http://scn.sap.com/docs/DOC-28803). this case, you not gonna sacrifice the functionality for the sake of performance.In
If you desperately need WS-RM adapter which is on ABAP stack or ABAP mapping or cross-component BPM, then the only option for you is classical Dual Stack installation. Do not believe the rumors that the dual-stack won’t be supported with the latest release. The good news is that SAP will continue to support the PI dual-stack with the upcoming releases. The PI dual-stack won’t go away on the short term; at least it will be supported until extended maintenance of the NetWeaver release 7.3 which is until 2020.