(Updated January 2019)
It's time to continue our story. Welcome back! In part 1 and part 2 of this series, we described the different paths for getting to SAP BW/4HANA and provided general recommendations as to what path makes the most sense for a give customer landscape. At those early days of SAP BW/4HANA, we had to leave out the details on the “how to actually get things done”. We have invested a lot of brain power, design sessions and development days and believe that we have come up with some pretty cool solutions helping all of our SAP BW customers to make their way to SAP BW/4HANA. This includes "followers" who haven't touched their SAP BW system for many years running on old disk- and row-based databases.
In this blog, we will focus on the "System Conversion" path for single SAP BW system. Net new implementations and landscape transformations with several SAP BW systems will be covered in future blogs. Let's dig into the details on how to convert your system to SAP BW/4HANA.
A Look Back
The major focus for building SAP BW/4HANA was simplification. Only 4 of the previous 10 object types use to model a data warehouse with SAP BW are available in SAP BW/4HANA. What do you do if you used some of the 6 obsolete object types, like InfoCubes? As a first solution, we provided a "data flow copy tool" that allows you to setup a second data flow but use only object types that are compatible with SAP BW/4HANA. In other words, it would use only Advanced DataStore Objects for persistency and CompositeProviders for the virtual layer to be queried. However, this tool had some shortfalls: All objects got new names and just empty shells were created. You still had to reload data yourself. Obviously, this could be only a temporary solution.
Next Steps
We have taken the transition process to a whole new level. If you have participated in the openSAP course “Modern Data Warehousing with SAP BW/4HANA”, you already heard about two new options for SAP BW customers. If not, I highly recommend spending a few hours to complete the informative course. The first option is the so called "In-place Conversion", which is primarily targeted for customers with existing SAP BW powered by SAP HANA systems. The second option is the "Remote Conversion", which appeals most to SAP BW customers running older releases or databases other than SAP HANA. Recently, we added a third option, the so called “Shell Conversion”. The following figure provides an overview and comparison of these options:
We understand the complexity of these scenarios and are taking a comprehensive approach to cover the transition processes end-to-end. To keep it as simple and straight forward for you as possible, In-place as well as Remote and Shell Conversions are based on the Task List Framework. This framework allows us to define and ship sequences of technical tasks that can then be executed in a customer system. We have used task lists in the past for SAP BW Housekeeping or Post Copy Automation, for example, quite successfully. The generic nature, great monitoring capabilities, and options for customization and customer specific extensions make it an excellent choice also for the system conversion processes.
Project Phases
To better understand the transition process, we defined a high-level plan and activities that we recommend following in this sequence. The steps are aligned with the SAP Active methodology. During the Discover and Prepare Phases, you check general system requirements, complete the maintenance planner (to get the required stack.xml file and download the software packages), check your original SAP BW system, and perform a custom code analysis. At the end of the Prepare Phase, you must decide, whether to take the In-place, Remote or Shell Conversion path.
In-place Conversion
The In-place Conversion starts with your SAP BW powered by SAP HANA system. The minimum release is 7.5 support package 5.
If your system is not running on SAP HANA or on a lower release or support package, and you decided to do an in-place conversion, then a prerequisite step for the in-place conversion is a migration to SAP HANA and a release or support package upgrade (often both can be combined). For information on the migration of SAP Business Warehouse to a SAP HANA database, refer to the End- to-End Implementation Roadmap SAP BW powered by SAP HANA.
The first step of the In-place Conversion process is to install the SAP BW/4HANA Starter Add-on. As a second step, you will implement the SAP BW/4HANA Transfer Cockpit on your system. After the installation, the several modes are available in the SAP BW system, which define the road to SAP BW/4HANA:
BW mode
- System works like regular SAP BW system without restrictions
Compatibility mode
- Existing scenarios can continue running as before but object types not available in SAP BW/4HANA cannot be transported (i.e. moved to production) unless you explicitly whitelist them
B4H mode
- Only SAP BW/4HANA compatible objects available in the system
Ready for conversion mode
- Final preparation for system conversion
To help you transition your SAP BW system from one mode to the next, we provide a pre-check program that scans the entire system for incompatibilities and creates a to-do list for you. If to-dos are completed and "all is green", you can switch to the next mode. It depends on your system configuration what kind of to-dos you get and how many. One thing is for sure: the older your system, the longer the to-do list and the more activities will be required. But don't be scared even if thousands of items are highlighted. This is where the Transfer Cockpit and its Scope Transfer Tool come to the rescue. The Scope Transfer Tool is based on a task list that lets you select objects and get them automatically converted to HANA-optimized counter parts. The process keeps the object names intact (as far as possible) and brings all data along (*). Isn't that nice?
We know that our customers love to "code". Did you follow best coding practices, used APIs instead of direct SQL on generated BW database tables, didn't call unreleased functions in standard SAP BW code? If yes, your custom code will be in good shape. However, if not, then the simplification brought by SAP BW/4HANA might have a significant impact on your programs. You will have to adjust your custom code accordingly. Help me! We heard you and developed a Code Scan Tool, which is available in the SAP BW/4HANA Transfer Cockpit. It will find if and where in your custom code you have referenced for example InfoCubes or classic DataStore Objects or called SAP functions that are obsolete in SAP BW/4HANA.
Once your system is fully HANA-optimized and your custom developments adjusted, the system can be switched to B4H mode. You can remain in this mode until your cut over day to SAP BW/4HANA. That's when downtime for your business begins. You will switch to "Ready for Conversion" mode immediately followed by the technical system conversion to SAP BW/4HANA. There will be a few post conversion tasks and clean-up and then... ta da... Your system is live on SAP BW/4HANA! Altogether, this final phase should take only a few hours.
Remote Conversion
If after the discover and prepare phase you decide for a remote conversion, then the next step is to install a brand-new SAP BW/4HANA system. We have a task list available for you that will automate and therefore greatly simplify the initial system setup. This is the beginning of a parallel run of old SAP BW and new SAP BW/4HANA systems. Remember, this approach will work for any SAP BW system with release 7.3 or higher and any database platform that your system is running on.
You can now use the Transfer Toolbox to select data models and flows out of your existing SAP BW system and transfer them over a remote connection to the target SAP BW/4HANA system (*). This is where you can choose: your chance to build a clean system, leave old and unused objects behind, and reduce unnecessary layers of your data warehouse. We are again using a task list that begins with a scope selection followed by a process to find all dependent objects like transformations, source systems, DataSources, queries, etc. All objects will then be transported to SAP BW/4HANA and this is where the magic happens. We import InfoCubes and classic DataStore objects and turn them on the fly into Advanced DataStore Objects. MultiProviders will become CompositeProviders. Nice! Since we want to run in parallel, the remote task list will also convert and reconnect source systems. This works very similar to the approach we used for running parallel systems for migrations to SAP HANA that you might be familiar with (Post Copy Automation).
In a subsequent step, we will use the SAP BW/4HANA Conversion Cockpit to also bring the data over from SAP BW and convert the request management (from Request IDs to Request Transaction Sequence Numbers). This tool is developed by the SAP Data Management & Landscape Transformation group and currently in Early Adopter Care. General availability is planned for end of Q1/2019.
Together with your data models, it makes sense to transport related custom developments and adjust them accordingly to work with the new HANA-optimized models and SAP BW/4HANA. If your original system is not on SAP HANA, we recommend to also HANA-optimize your ABAP code at this time. Of course, this is another chance to clean-up and leave old sins behind, right?
Once you completed the transfer of all required objects, developments, and configuration, you certainly want to test that all works well in your new SAP BW/4HANA system. It's all low risk, since it runs in parallel with your existing SAP BW system, which remains unchanged. You should be able to compare both sides easily. All good? Tell your users to logon to SAP BW/4HANA and turn your old system off. Done.
Shell Conversion
Some customers like the Remote Conversion approach but want more flexibility when it comes to the data that should go into the new SAP BW/4HANA system. This is where a Shell Conversion is the way to go. It will bring over all data models and flows like a Remote Conversion. However, neither master nor transaction data are transferred. This gives you the following options: Re-load as much data as you like from your source systems, load data from original SAP BW system, or simply ignore historical data and start fresh. The Shell Conversion is already in general availability and works for SAP BW release 7.0 or higher.
Summary
We know there are a lot more details to cover, but this gave you an overview of how In-place, Remote, and Shell Conversions work in general.
For a presentation style version of this blog ("The Road to SAP BW/4HANA") and many more details on SAP BW/4HANA, please visit the SAP Community Network and check out the FAQ document.
A complete end-to-end documentation of the transition process from SAP BW to SAP BW/4HANA is already available in the SAP BW/4HANA Conversion Guide.
Best,
Marc Bernard
@marcfbe
(*) If you still have left-over data flows from the 3.x days, you will have to migrate them to 7.x functionality before the Scope Transfer Tool can be used. For Remote and Shell Conversion, this data flow migration has to be done in the original SAP BW system.
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