Quick Guide to SAP BW/4HANA Migration

[prem_shanker]

SAP BW/4HANA is SAP’s next generation data warehouse solution. It is entirely built on SAP HANA database. When customer wants to install SAP BW/4HANA, the question arises of which method is most appropriate. Generally, the “greenfield approach” (new installation of the system) or the System Migration approach come into question. System Migration which are “in-place conversion”, “remote conversion” and “shell conversion”.

In this blog we will be discussing how to Migrate current BW system to SAP BW/4HANA system.

Strategy 1: Same BW box we are upgrading to BW/4HANA system. This is called In-Place Migration i.e., we don’t have a separate server, the same BW Prod box will be upgraded to             BW/4HANA system. SID (System ID) will remain the same.

• Redesign your current applications. [i.e., current DSO to ADSO, current MP to CP etc.]


• Clean up and delete obsolete objects.


• Significant downtime for Production.

Strategy 2: Create a new SAP BW/4HANA system. (New SID) i.e., Install a fresh new system which is already on BW/4HANA.

• Carve out existing future-proof BW applications or build them from scratch again.


• Phase out existing BW system and roll out new BW/4HANA system.


• Almost zero down time for production.

 

Shell Conversion:

• Accelerated Greenfield Conversion.


• Transfer of selected data model without data transfer.

Remote Conversion:

• Brownfield Conversion


• Transfer of selected data model with data transfer

 

Different Paths for SAP BW/4HANA Migration

In-Place Conversion:

• Target group: customer who wants to change their current SAP BW system into BW/4HANA system and who are already on an up-to-date release (preferably 7.5 powered by HANA).


• This means that the customer gets to keep the existing BW system and transfer it so BW/4HANA system (keeping the SID).


• Approach without re-implementation, no disruption for existing business processes.


• SAP provides all the tools that is required to complete the migration process (BW/4HANA Transfer cockpit).


• Release requirements: SAP BW 7.5 SP05 powered by HANA, but recommended is the recent SP level.

Shell Conversion:

• Target group: SAP BW customer


• For customer who wants a fresh SAP offers an option to transport certain objects from the old BW to newly installed BW/4HANA. These objects will be transported into BW/4HANA supported objects during import into BW/4HANA system (ex:- Infocube à ADSO).


• New System ID(SID).


• No Data transfer will happen from old BW system (neither Master data nor Transactional data) Data has to be re-loaded from original source system.


• Release requirements: SAP BW 7.x(regardless of database).

Remote Conversion:

• Target group: Customer who wants to change their current SAP BW system into SAP BW/4HANA system and who are in older release and not on SAP HANA.


• Remote conversion means that customer builds up a new BW/4HANA system (new SID) and transfer BW objects (metadata) and data (master and transactional data) from original SAP BW system.


• Convert BW objects in newly installed SAP BW/4HANA system. Multiple persistent objects (Infocube, DSO etc) will be replaced by ADSO.


• No database migration or BW application upgrade required.


• Release requirements: SAP BW 7.3(regardless of database).

 

Right Path for Migration

Pre-Migration checks: -

SAP Note - 2383530: Conversion from SAP BW to SAP BW/4HANA

This is the central note for the people who are planning to move to SAP BW/4HANA.

This note delivers the tool for Migration “Transfer cockpit” [T-Code: RSB4HCONV].

SAP Note - 2575059: SAP Readiness check for SAP BW/4HANA.

Initial Step: Readiness check [Tool will check the details of what we are missing].

• This provides add-on compatibility and do compatibility checks.


• BW/4HANA Sizing


• Simplification Items (like IPAK’s are simplified as DTP’s, PSA’s are simplified as ADSO’s)

 

Transfer Cockpit [T-Code: RSB4HCONV].

Preparation phase: - Pre-Checks - Sizing reports, clean up reports, Scan codes (if any manual modification is required).

• This is independent of migration/conversion approach.


• The Pre-checks provides the list of all non-compatible objects on the line item level (with technical names).


• It also provides the information on which line item will be deleted by default, or need to be deleted manually or taken care by the transfer tool itself etc.

 

SAP BW/4HANA Transfer Cockpit

 

Realization Phase: - Which objects we need to migrate (scope Transfer), actual migration.

• This is different for each migration/conversion approach.


• This is actual migration step, and the conversion happens here.


• Deleting Technical content(ex:- 0TCT objects).

 

Steps for Migration

In-Place Conversion: When customer is already at BW on HANA latest version, one should be recommended to use In-Place Conversion. Prerequisite for In-Place Conversion is the Started Add on

SAP BW/4HANA Started Add on: -

• Pre-condition for BW/4HANA In-place migration.


• Added into the BW system which needs to be converted.


• Provide access to conversion tools and manage the conversion process.


• Technical Name of this component is BW4HANA.


• Basis person needs the authorization object S_RS_B4H to do the migration activity.
  
  
  
  • SAP Notes 2246699: SAP BW/4HANA started add on Pre-Requisite and Installations.
  
  
  • SAP Notes 2189708 Installable Adds-Ons for SAP BW/4HANA Started Add-on.
  
  
  
  

 

System Modes provided by BW/4HANA Starter Add-on

Transfer Cockpit BW System Mode

1. BW Mode:

• Default Mode as there is no restrictions.


• We can keep working on BW system.

2. Compatibility Mode:

• BAU Operation on BW can continue.


• As migration has started here any new development which requires creation or change in old type Objects (like Infocube, MP etc) is prohibited. However it is supported when activating BI content or importing objects from dev system.


• In case of emergency any change in old object can be possible as an exception and is attained by adding it in the whitelist (report RS_B4HANA_WHITELIST_MAINTAIN).


• The SAP BEx tools can still be used.


• All the classical objects are transferred into the BW/4HANA compatible objects.


• Length of the time one will spend: Few Months[Largest time in this Mode].

3. B4H Mode

• There are no classic objects anymore in the system.


• No more imports of unsupported objects are possible.


• The SAP Bex tool cannot be used anymore.


• Registering objects in the whitelist will not be relevant anymore as there are no unsupported objects in B4H mode.


• Virtual providers for BPC are still allowed.


• Length of the time one will spend: Few Weeks.

4. Ready to conversion Mode.

• All system wise clean-up activity is successfully completed.


• The system is fully prepared to start the conversion of the software component.


• Length of the time one will spend: Few Hours.

Task Processed during switch from Compatibility Mode to B4H mode.

• Transfer 3x queries to 7x queries.


• Transfer datasource for personalization.


• Delete available RDA (Real Time Data Acquisition) configuration. It is replaced by Streaming Process chains.


• Transfer Infoobject Catalog to Infoarea


• Delete RSDDB Index


• Set B4H mode.

 Task Processed during switch from B4H mode to Ready for Conversion Mode.

• Delete D(Delivered) version of all Objects.


• Virtual version of BPC is finally deleted here.


• Obsolete source systems are deleted. New source system types are in BW/4HANA now.


• Delete PSA table for datasource.


• Clean-up Error Stack.

 

Reference

https://help.sap.com/doc/c8e1ac37fee64e0f887a2d6d6af32a33/2021.00/en-US/SAP_BW4HANA_2021_Conversion_...

https://blogs.sap.com/2021/02/02/sap-bw-4hana-conversion-steps-to-consider/

https://visualbi.com/blogs/sap/sap-bw-hana/sap-bw4hana/bw-4hana-migration-options/