Introduction

BW/4HANA is available now for more than 2 years and I got the feeling that more and more BW users are starting to think how to get there. If you do not start from scratch with BW then the process to BW/4HANA from any previous BW release is a completely new experience since it is much more application driven compared to the BW upgrades, we know from the past.

Marc Bernard provided a blog series on this topic called “The Road to SAP BW/4HANA”. This is a great starting point to get into the topic. Unfortunately, there is not the one road to BW/4HANA. Depending on your own set-up several roads are possible. Each will have specific pros and cons and the decision which road to take is a very individual one. In this blog I would like to share some ideas/thoughts which might help you to choose the right road for your scenario.

Thoughts/Questions

Is BW the right tool?

For someone like me working for more than 16 years with BW asking this question is strange. In my case the answer is obvious . However, the change from any BW to BW/4HANA is significant and therefore the effort (money and time) you must spend, will be also significant. On the other hand, staying with an “old” BW release is not future proof. I can imagine, that there are scenarios where other solutions make more sense than BW. This is now a good opportunity to evaluate your requirements and define a strategy in this area.

What can you do to prepare for BW/4?

If you answered the first question with yes, then it is time to get to know your system. Regardless what conversion approach you will follow, there are some analysis/actions which I would highly recommend doing in your existing system upfront. Just a few examples:

• Which queries/data models are used and shall be kept?
• In which state are these data models?
  • Would you build them with BW/4HANA (at least) in a similar way?
• Are there any larger logical inconsistencies in your data models? For instance, wrongly modelled InfoObjects?
• What parts of your system are not used anymore and could be deleted?
  • If you have been looking for the “BW hygienics” in the past, it will be a lot easier.

In combination with your current set-up (BW Release, HANA or AnyDB etc.) you should get a feeling which approaches might work.

Furthermore, you need to think how you want to work in your BW4 system in the future. It is now the perfect time to get your guidelines and naming conventions updated. Data modeling in BW4 is different compared to BW 7.0, however It can (should) be almost the same if you are already on BW 7.5 on HANA.

And finally, it is time to revisit your front-end strategy. Whether it is Analysis Office, Lumira, SAC or 3^rdparty software: You probably can use them already with older BW releases and start to eliminate things like BEx Web or BEx Analyzer.

When should you start with the conversion?

The answer to this question is two-fold. With the preparation you can and should start now. However, if you are anyway using a later BW release on HANA you can probably already work right now in a kind of BW/4 mode. By doing this you reduce, if not avoid, future conversion efforts.

From a feature perspective, I assume, there is no real need for the majority of customer to move towards BW/4 right away. If this applies to you, you can take your time. This gives you the flexibility to stretch the project over 1 or even 2 years.

Unfortunately, in some companies it is not possible to run projects in such a way mainly because of budgeting reasons. Also, if you are on an older BW release on AnyDB and you want to move directly to BW4, then the situation is probably different.

Will Greenfield solve all problems?

I’ve had already quite a few discussions around the different approaches and it seems that many people prefer a greenfield approach, even if their current system has almost got perfect pre-conditions for an In-place conversion. Setting up a new system is surely always an option, and, in some cases, it makes sense.

However, if I’m running a single BW landscape right now, I would prefer to stick to that. Such greenfield projects do have the tendency to last longer and I’ve seen already some cases where the old systems were running for much longer than originally expected.

I would suggest evaluating alternative approaches. For example, I could imagine doing a kind of brownfield in an existing system. To some extent being based on existing data models and some re-developments. Such an approach would also support re-naming and re-modeling where necessary. You would re-use what is already there and delete what is not needed anymore.

What can you expect from the Transfer Tools provided by SAP?

Important for the evaluation of the different approaches is to know the role of the Transfer Tools. The Toolbox is currently evolving very quickly. However, I would not count too much on them. Why?

• You create more or less 1:1 copies of the existing data models. My assumption is that every data model created on a BW before 7.4 and on AnyDB needs rework. What is the purpose of a new BW/4 system if the data models are still the same as before?
• Within the tools you have no possibility to adjust the models. Any changes must be done manually and at some point, you might be faster by copying.
• The conversion handling can also be very tedious depending on your existing system set-up. I have seen scope list of more than 50.000 objects by choosing a single object to be converted.
• The conversion process must be controlled, otherwise you will start to block yourselves.
• Now (this will surely change) it is very time consuming to keep the tools updated. Implementing/updating notes is currently daily business.

Final Thoughts

• The complete migration is very individual. There is not the one recipe which you can easily follow. You need to develop your own approach.
• Preparation is everything. Understand your current system.
• In many cases there is no need to rush.
• Do it!

https://blogs.sap.com/2018/11/06/which-road-to-take-to-bw4hana/