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DMO: shadow repository on target database for conversion to SAP S/4HANA 1909

Abstract:

In some cases, SUM will create the shadow repository on the target database in the future.
This blog provides background information as well as the current status of this new approach.

Introducing the shadow system and shadow repository

The Software Update Manager (SUM) has several means to reduce the downtime of maintenance events like update/upgrade, database migration, or system conversion. One of these means is the shadow system.
A shadow system basically consists of a shadow instance and a shadow repository:
  • The shadow instance is an additional ABAP instance which is created by SUM on the application server on which the SUM was started. It is used to prepare steps executed during the downtime.
  • The shadow repository exists on target product version level. This means that the shadow instance must use the target kernel to create the shadow repository with potentially new object types.

The shadow system is alredy created and exists during uptime processing of SUM. As a consequence, the downtime is reduced.

[i] You can check this blog for an introduction to the shadow system, but this description does not yet cover the aspects discussed below.

Until now, SUM creates the shadow repository on the source database specifically for the migration scenarios Database Migration Option (DMO), and System Conversion to SAP S/4HANA for source systems with no SAP HANA database. (Note that non-migration scenarios have only one database, so that is no differentiation of source and target database is needed.)

This will change for a system conversion to SAP S/4HANA 1909 with SUM 2.0 SP 06 (general availability planned for mid of September 2019): SUM will create the shadow repository on the target database. (Again: This only applies if the source system is not yet on SAP HANA database and a database migration happens. Only then we have a source and a target database).

 

The figure illustrates:

  • SHD REP: the shadow repository
  • PAS: the primary application server
  • PRD REP: the current (productive) repository of the source system

SAP S/4HANA 1909 and the ABAP kernel

SAP S/4HANA 1909 uses SAP kernel 7.77. This kernel version works exclusively with SAP HANA as database. As the shadow instance must use the target kernel, it is obvious that the shadow instance for SAP S/4HANA 1909 can’t work with a database other than SAP HANA DB. That is the reason why SUM has to create the shadow repository on the target database for a migration scenario targeting SAP S/4HANA 1909.

Note: SAP Kernel 7.73 as well only supports SAP HANA as database, but it can be used for the shadow repository on source db in the conversion process targeting SAP S/4HANA 1809.

No changes for SUM handling

If you have used SUM 2.0 for a system conversion before, you will not experience any difference in the dialogs concerning the shadow system handling with SUM 2.0 SP 06. So, there is no user choice or parameter on the shadow system creation – SUM will simply do what is required.

(There is a new dialog sequence introduced with SUM 2.0 SP 06 – described in this blog – but this is not related to the shadow system.)

Advantages for conversions to S/4HANA 1909

The shadow repository created on the source system was the reason for some migration requirements concerning the source database. As an example, Oracle 11.2 database on source systems had to be upgraded to version 12 prior to the conversion run (or NZDT had to be used). And in some cases, it was required to extend the tablespace of the source database to create shadow repository. These requirements are now obsolete, when the shadow repository is no longer created on the source database. Good news!

That was the easy part – now to the fine-print part of the story …

Additional aspects of the story

SUM 2.0 SP 06 is the first SP version of the tool that uses the shadow repository on the target database – but not for all possible cases. Let me clarify some aspects and typical questions:

These scenarios are planned to be supported in later SP versions of SUM 2.0.

Boris Rubarth
Product Manager SUM

28 Comments
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  • Thanks Boris !! This is amazing, this cuts down lots of effort during source system preparation in a conversion project. On the other hand, DMO with system move is a restriction gives me a frown face. Can you please share a rationale for this?

     

    Regards,

    Prithivi Raj

    • Hi Prithivi,

      up to now, “DMO with system move” had created the shadow repository on the source system landscape. This is no longer possible, as we can’t assume to have a connection to the target (SAP HANA) database from the source landscape. The approach is more complex to be switched.

      Regards, Boris

  • Nice read, also for me as a non-basis person.

    So far, as an ABPAer, my contact with shadow instances is that during upgrade, there might be some  PARDIST_SHD DISTRIBUTION ERRORS, fellow basis-person will let me know,

    and I’ll AdT into the shadow instance to activate some CDS-views.

    Best
    Joachim

    • Hi Joachim,

      good part of the story is that connecting to the shadow system does not change. It uses the shadow instance, and their location does not change.

      Best, Boris

  • Thanks Boris. This is great feature indeed! since lots of customers has lesser resource on source system and you know source is going away, no sense to add resources… This is Amazing!!  Thank you again , Amit Lal

  • Hello Boris

     

    Thank you for a great blog.

    We are thinking of migrating to S4HANA/ Azure/ RHEL

    from ECC6.0 EHP6.0/Oracle 11.2/On-premise/RHEL.

     

    Reading youre previous blogs and sap notes, i know that for my above scenario, i need to use DMO with system move option and system update option.

    So if from SUM SP06, system move option is not supported (when SP06 is great creating the shadow rep on target), then we dont have choice to go like below??

     

    //Use SUM 2.0 SP05, go to S4HANA 1809 on Azure with system move option and afterwards update to 1909??

     

    Can we use normal DMO when going from onpremise to Azure cloud, so that we can use SUM 2.0 SP06??

     

    Regards

    • Hi Kotaro,

      thanks for your question.

      • yes, as you state “DMO with system move” is not applicable with SUM 2.0 SP 06 for target SAP S/4HANA 1909
      • yes, you may use SUM 2.0 SP 05 for DMO with system move targeting SAP S/4HANA 1809 on Azure (and do upgrade to 1909 then), but you may as well use SUM 2.0 SP 06 for that, as SP 06 supports DMO with system move if target is not S/4HANA 1909
      • No, plain DMO does not support a data center move or move to cloud (IAAS) as written in the respective SAP note for DMO

      Regards, Boris

      • Hello Boris,

        Thank you so much for an quick and informative reply!

        Understood about your reply!

         

        Btw, i heard when i was talking on the SAP expert chat that

        from SUM 2.0 SP06, the os of application server of the target system has to be supported for the target SAP release only according to PAM, not also the ap server of source system.

        Is it correct?

        • Hello Kotaro,

          sorry, I guess I did not yet understand your scenario.

          For a normal DMO scenario, the application server host remains, so there is no difference between AppServer of source and AppServer of target system.

          Regards, Boris

  • Hello Boris,

    In case of having HANA 1.0 on source system, will customers continue to have pre-requisite of updating HANA to a compatible DB version of S/4HANA Product (HANA 2.0), ahead of the Conversion Process?

    Can you kindly share if SAP is planning also to extend the possibility of having contemplated scenario below, with this new fancy feature?

     -> Source-> ECC 6.0 EHPxx running on HANA 1.0 SPS12

     -> Target-> S/4 HANA 1909 running on HANA 2.0 SPS4

     Kind Regards,

    Claudio Quina

    • Hi Claudio,

      thanks for asking – the requirement to start on SAP HANA 2.0 (if source is already on SAP HANA database) remains. The SUM never upgrades the source database software level, and this is true for SAP HANA db as well.

      Kind regards,

      Boris

  • Thank you for your always interesting and helpful articles,

    I am preparing for a conversion from ECC 607 to S/4HANA 1909, my source DB is ORACLE 12.

    From my understanding S/4HANA 1909 is based on ABAP Platform 1909 (SAP_BASIS 7.54), I am reading the note 2798588 – Database Migration Option (DMO) of SUM 2.0 SP06 to understand the prerequisites and found a confusing statement when your target database is HANA:

    Oracle version 11.2 or higher if target SAP_BASIS is 750, or if target SAP_BASIS is 7.54 or higher

    Oracle version 12 or higher if target SAP_BASIS is 751 or higher and lower than 7.54

    Does this mean that my current Oracle version is not supported to run the conversión to S/4HANA 1909?

    Thank you in advance for your comments

    • Hi Jorge,

      sorry to say that I do not understand your concern:

      • Oracle version 11.2 or higher is required for target SAP S/4HANA 1909 (on basis 7.54)
      • You have Oracle 12
      • Oracle 12 is higher than 11.2

      Where is the question?

      Thanks, Boris

  • Hello Boris,

    Thanks for the excellent blog and keeping us updated with the latest features.

    1. When will the System move option supported, any rough timelines.

    2. When can we expect to support 1809 SP02

    3. How much downtime we can save, creating shadow system on the target, any rough estimates.

     

    Thanks & Regards,

    Deepak Rade

    • Hello Deepak,

      thank you for the feedback.

      Concerning your question:

      1. I assume next year
      2. SAP S/4HANA 1809 is supported with all available FPS
      3. Shadow system is anyhow created during uptime, and the new approach (shadow repository on target database) does not change this.

      Regards, Boris

    • Hello Mahesh,

      sorry to say that we can’t provide a GA date yet. We will announce it as soon as we are confident, but it depends on the outcome of the development and validation tests. My personal hope is that it will be somewhere around mid of 2020 or Q3, but let’s see.

      Regards, Boris

      • Thanks Boris

        But what options the customer has now when they would like to Migrate to S/4 1909 on SAP HEC.

        1. Do a In place upgrade to 1809 with On Premise and then use Export/Import to move the Database to Cloud on S/41909.
        2. Migrate to 1809 first with system Move to Cloud and then upgrade the system to 1909.

        The customer does not have much downtime and hence both the options seems to be a time consuming. Also the customer wanted to go live in April 2021 and cannot wait until 3rd Quarter for 1909 Support.

        Let me know if there are any other best options with your experience.

        Mahesh Shetty

  • Hello Boris,

    thanks for your blog and to inform us about last development on SUM/DMO.

    I’m in the same scenario of migration of ECC6 Ehp5 to S/4 1909. Without “System move” option it’s for me a regression because of old infrastructure Source System.

    As the migration should be done ‘in-place”, our current infrastructure is on OS (Linux RHEL5), DB (Oracle 11.2.0.3) and Kernel (7.22) infrastructure on the source must be compliante and upgraded with a target system before the beginning of the SUM process. It means new project with downtime, non-regression tests, etc before S/4 migration project…

    “System move” is really a very good approach to migrate smoothly from old infrastructure system.

    Hope this option will come soon because it’ becomes an issue for S/4 Migration

    thanks a lot,

    regards,

    Sacha Gosselin

     

     

  • Hello Boris,

    many thanks for this very informative overview about the DMO procedure for S/4HANA 1909!

    Is there any schedule when the DMO with System Move function will be available?
    This is such a useful feature we don’t want to miss for our upcoming S/4Conversion.

    Thanks and best regards
    Anne

  • Dear Boris,

    I am now doing an S/4 HANA 1909 conversion from ECC6.04 on HP-UX IA64 based Oracle 12g Database. The Target S/4HANA 1909 based on Linux platform X_86. SUM SP07.

    System tell me that Shadow system is not allowed in the HPUX for S4 HANA version over 1709. I think that the shadow repository will be created in the HANA server. Do you have any idea on it?

     

    Best Regards

    Alan Zhu

     

  • Hi Borris,

    The only place I can seem to find conclusive info on DMO with System Move not being supported for 1909 is with you via this article or answers to other questions in this forum.

    I don’t see anything concrete listed in the release notes, restrictions or the latest versions of the SUM and DMO guides for SP06 or SP07 – in fact these guides actively talk about DMO with System Move which I think it what is confusing a lot of people. Is it just me, am I missing a reference somewhere?

    Happy to post this as a separate question if needed or to log a formal note if needed since I have a customer with the same questions and I’m referring them here which is good since you are the SUM product manager 🙂

    Thanks in advance, I find your content very professional and thoughtful.

    thanks,
    Paul

    • Hi Paul,

      You can find this information in SAP Notes 2798588 – Database Migration Option (DMO) of SUM 2.0 SP06 and 2840346 – Database Migration Option (DMO) of SUM 2.0 SP07

      Requirements for Target System and Target Database:

      • Target Database: SAP HANA and SAP ASE only
      • OS of PAS host: Any Unix-based or Windows operating system
      • “DMO with System Move” is currently not supported for targeting SAP S/4HANA 1909

       

      regards,

      Sacha G.

       

    • Hi Paul,

      thanks for asking, and thanks to Sacha for providing the answer.

      I take this question as an opportunity to advertise our landing page for SUM: https://support.sap.com/sltoolset

      You find a section with up-to-date information on SUM related scenarios with links to respective SAP Notes, guides, blogs, and a link to a dedicated page on SUM with more information.

      Regards, Boris