Dual-stack system
SAP system that contains installations of both Application Server ABAP (and Application Server Java (AS Java).
A dual-stack system has the following characteristics:
- Common SID for all application servers and the database
- Common startup framework
- Common database (with different schemas for ABAP and Java)
Note: SAP does not recommend to setup Dual Stack Systems except if necessary (e.g. Solution Manager)
Dual stack is required for
- PI/XI
- Solution Manager
- Mobile up to NW 7.0
Optional Use case
- BI 7
- ESS scenarios in dual stack
- Java Usage Types in NetWeaver Systems (e.g. Enterprise Portal)
SAP strategy
- Running SAP NetWeaver application components in single stack
- Exception: Solution Manager will stay dual stack
SAP Application Server Setup recommendations
- Setup SAP systems as single stack whenever possible
Single Stack system:
Single Stack system is defined as SAP system with either SAP Netweaver as ABAP or as Java as in run time.
For example:
- Single stack Java system is SAP Enterprise Portal (EP)
- Single stack ABAP system is SAP (ECC)
Single Stack or Dual Stack
Java (Single) Stack alone:
Almost all standard adapters including HTTP, IDOC and Proxy are all available in this stack. You need to use Integrated Configuration object for this. You are basically going to use Advance Adapter engine alone for the entire processing.
- No persistence steps here. So you would improve performance many folds for sure.
- Throughput is also improved very much.
- Since 7.3, Solution Manager is available for monitoring in addition to RWB and NWA. So monitoring would not be issue.
- If you are looking for real performance improvement, Single stack Java to go.
- Abap mapping is not supported.
- Message split to multiple receivers are not completely supported.
- BPM interfaces are not seamless migration here. SAP 7.1 and lower versions support BPEL whereas 7.3 support BPMN standards. So you might have to tweak a bit to modify existing interfaces here
Dual Stack:
If you need some specific interfaces to handle only java stack, still that is possible and increase the performance. Also if you have lot of existing interfaces that requires BPM interfaces, ABAP mapping, Multiple split /branching etc. Developer decides according to the requirement.
Useful points from Dual stack and Single stack:
- Three different licenses for Net Weaver BPM requires a separate licensing- Double stack PI, Java Only PI and PO (PI + BPM and BRM)
- CCBPM is not supported in single stack for that need to redesign andrebuild them in Net Weaver BPM. You need Single JAVA Stack+BPM installation model for this.
- If you go to single stack, you have to replace the ccBPM processes. There is no migration for this, also need to replace any ABAP mappings and developments. But for the configuration there should be a migration tool available to convert classic configuration objects into Integrated Configuration objects
- On a single stack you have different configuration objects which are called "Integrated Configuration". The classic configuration objects cannot be used on the single stack for that need to do migration.
- Upgrade path from 7.1.1 (Dual Stack) to PO installation option or single stack installation option need to do migration.
- ABAP proxies and XSLT mappings fine in single stack.
Difference between Dual stack system and Single Stack system:
- Single Stack will support all adapters except WS RM and ccBPM for this you can still integrate scenarios of IDOC and RFC using single stack.
- If you have any scenarios which require either ABAP Mapping or ccBPM you can go with the option for dual stack.
- Unless BPMN is set up that is ccBPM scenarios are supported in Single Stack you cannot upgrade dual stack scenarios to single stack.