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Author's profile photo Hafizur Rahman

SAP S/4HANA System Conversion and Downtime

Downtime Options for System Conversion

The objective of this blog post is to discuss available downtime options for System Conversions, and to discuss guidelines around SAP ERP System sizes when considering a suitable option.

So for meeting system downtime requirements, SAP offers following options for System Conversions:

  • Standard conversion for smaller SAP ERP Systems
  • Downtime-optimized conversion for midsize and large systems
  • Minimized downtime service by SAP Digital Business Services for extra-large systems

With regards to size of SAP ERP systems, here are some guidelines:

  • A small system would have of data volumes of 5 TB and below.
  • Extra-large systems would have of data volumes of 20 TB and above.


image: Conversion Options and Cutover phases,
image source: “Mapping Your Journey to SAP S/4HANA” see reference


Standard Conversion with Software Update Manager

The common multipurpose Software Update Manager (SUM) tool is used for general software maintenance, however it can also technically convert an SAP ERP system into a SAP S/4HANA system. It can also combine migration, conversion and software upgrade in a single run.
The programs that help SUM carry out most of the conversions are XPRAs and XCLAs.
Important to note that conversion of financial and material ledger data takes place in special steps after the SUM conversion procedure. General conversion runtime can be reduced by applying the many optimization capabilities of SUM.


image: SUM tool Option Standard


Downtime-Optimized Conversion with Software Update Manager

Converting data into the new SAP HANA data structures can take a longer runtime for larger systems. In terms of negotiating a cutover window, we should have a good idea of expected runtime from our Conversion Test Cycles, however some recommendations for larger systems could be:

  • from 8 hours (one factory shift)
  • to 60 hours (Friday 6 pm. to Monday 6 am)

So this window would include all phases of the cutover procedure including the actual downtime.

To help make cutover window achievable using the standard Software Update Manager tool, SAP has developed the downtime-optimized conversion option which converts large parts of the SAP ERP data during uptime and by using the record-and-reply technology to incorporate data changes. So using the common tool set we should still be able to meet general minimized downtime expectations.


image: SUM tool Option Downtime-optimized


Minimized Downtime Service by SAP Digital Business Services

SAP Digital Business Services offer the ‘Minimized Downtime Service (MSD)’ this is designed to help customers with extra-large systems, these would have:

  • Data volumes over 20 TB
  • A large data footprint in finance and/or logistics
  • A high volume of application changes.

For more details this service offering check SAP Note “693168 Minimized Downtime Service (MDS)”


Transition to S/4HANA is a challenge, however there are some excellent practical guides from SAP, below is one of them and is the source of information for this article, enjoy ?

Mapping Your Journey to SAP S/4HANA – A Practical Guide for Senior IT Leadership


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      Author's profile photo Arunkumar BP
      Arunkumar BP

      Good blogpost.

      Few queries.

      It was said about small system would have of data volumes of 5 TB and below.

      where would the data volume between >5TB and < 20TB fall?


      also there are some blog post in these topics. Is this supplementing the others? case/



      Author's profile photo Hafizur Rahman
      Hafizur Rahman
      Blog Post Author

      Hi Arunkumar

      I think ERP Systems of size >5TB to and <20TB would fall into Medium/Large category.

      Thank you for feedback and blog links - much appreciated.