SAP S/4 Hana Conversion – III – Realize
Welcome to my third and final blog of SAP S/4 Hana Conversion series.
In this blog we will take a deep dive into Realize phase of SAP S/4 Hana Conversion. This blog is the continuation of my previous blogs SAP S/4 Hana Conversion – I and SAP S/4 Hana Conversion – II – Prepare ;Please read previous blog first to get better understanding of this blog.
In this blog we will discuss about Realize phase of S/4 Hana Conversion. Realize phase is all about SUM prepare, run and follow-up activities as shown in below figure.
Before we talk further about the Realize phase of S/4 Hana Conversion lets first clarify and answer some of the basics about SUM tool in relation to SAP S/4 Hana Conversion –
Which SUM version is suitable for conversion?
SUM 1.0 is here for a while and used for AS ABAP, AS JAVA and Dual stack system upgrade and also can be used for ABAP DB heterogeneous migration, when used with Database migration option commonly referred as DMO. Before we dive deep into Realize phase activities lets briefly touch upon SUM versions and usage. As you see in below figure SUM 2.0 can only be used for ABAP systems whereas SUM 1.0 can be used for SAP Dual stack, JAVA system and ABAP system, where target upgrade version is NW 740 and Lower.You don’t have to worry about choosing wrong version as maintenance planner will provide the respective version for maintenance activity .Needless to say that SUM 2.0 will be used for SAP S/4 Hana Conversion.
Using SUM with DMO or without DMO for conversion?
If your source ERP system is already running on SAP HANA DB, you will be performing conversion without DMO. If you are running ERP on any other supported DB than Hana, in that case you are required to use DMO for conversion. SUM tool provides a single process to migrate and convert into S/4 Hana. The main benefits of DMO are:
- Simplified migration steps
- System update and database migration combined in one tool
- Reduced business downtime
- The source database remains consistent, thus a fast fallback is possible
Note: – You can also use SUM with Migration only option by adding parameter migration_only =1 in SAPUpadd.par file in sum bin directory.
What is the difference between Standard V/S Downtime-Optimized Conversion?
The downtime of a system conversion run from SAP ECC 6.0 to SAP S/4HANA is dominated by the migration part and the data conversion.
Downtime-optimized Conversion aims to drastically reduce the downtime for a system conversion to SAP S/4HANA. This is achieved by executing SUM downtime activities in uptime, like migration (and data conversion. End user activity in those uptime phases is considered by SUM and replayed, partially in uptime, partially in downtime.
Prerequisite check tool – Prerequisite check v/s Prerequisite check extended?
Scenario strategy dialogbox also allows to run the prerequisite checks to ensure there is no issues in the system before you start with actual conversion. It is advisable to run prerequisite tool check for at least your first (SBX) system conversion where you absolutely have no idea what kind of issues you are going to face down the path. Prerequisite check tool provides two main types of checks. Prerequisite Check Extended performs extensive checks and executes the SUM uptime phases of the conversion run and takes the same time as the real conversion. Whereas the Prerequisite Check performs quick and non-invasive check, but it only checks the OS level, DB level, and SPAM level requirements. When Prerequisite check extended is completed SUM doesn’t start the downtime but automatically executes as reset. You can see all the checks executed with results (error) in SUM log directory in CSV file and get an opportunity to resolve them before your next real SUM run.
SUM benchmarking tool
It is a good idea to benchmark the time required for migration and conversion using SUM Benchmarking tool. SUM benchmarking tool gives an idea about the downtime. It allows a quick migration test, skipping the update part of DMO. You execute it prior to the DMO run to test the migration rate, and adjust the number of R3loads. Options allow to only export data, or to only migrate part of the database. It creates the MIGRATE_UT_DUR.XML files that can be used for the next DMO run to optimize the parameters.
You can run multiple benchmarking run and optimize each run to get to desired migration transfer rate. It is advisable to start with first small sample of data and then move to bigger sample for export and import benchmarking. You can start the benchmarking tool with this URL – > https://<hostname>:1129/lmsl/migtool/<sid>/doc/sluigui
SUM Planning & preparation for S/4 Hana conversion
SUM planning here is centered on the plan to reduce the downtime to minimum and running /migration /conversion efficiently .It is recommended to start planning your update at least two weeks before you start with the update preparations phase. Here are some of the top items that you need to plan before you start to execute SUM preparation roadmap –
- Read important SAP note – 3126522 – Add. Info. on converting to SAP S/4HANA using SUM 2.0
- Download all files from Maintenance planner along with stack.xml in download directory.
- Extract SUM directory.
- You can also add Migrate_DT_DUR.XML and UPGANA.XML from previous SUM run .
- Download Latest HANA Database Client Software and setup on server where you would be running SUM process.
- Check and provision required storage .You need at least 20GB for DIR_TRANS and 40 GB for SUM and Download directory.
- Request and download Migration Key from SAP.
- Decide on scenario strategies mode (Standard v/s Downtime-optimized)
- If using Downtime-optimized conversion, prepare the text file that lists the tables for uptime conversion that will be requested by sum process.
- Create an incident and get the password from SAP to authorize the use of Downtime-optimized conversion.
- Prepare Target Database SAP HANA
- You should simulate the uninstallation by running test scenario in saint to ensure no custom config is affected by the uninstallation.
- Request Permanent SAP License
SUM Tool Execution
The SUM consists of 6 Roadmap Steps. Roadmap Steps Extraction, Configuration, and Checks form the preparation part. Roadmap Steps Preprocessing, Execution, and Post processing form the actual upgrade part.
To make sure that all requirements are met, run the preparation roadmap steps of the Software Update Manager (Welcome, Select Target, Confirm Target, Execute Process, Initialization, Extraction, Configuration, and Checks ) as soon as possible. You can reset and repeat the preparation roadmap steps as often as you need by choosing back before you start the actual update in roadmap step Preprocessing. Do not perform any additional actions during the Software Update Manager run that could cause it to run less smoothly.
During the preparation roadmap you are required to provide multiple input to build SUM parameter list for selected scenario strategy. You are required to provide the DDIC 000 password and password for SAPService<SID> for windows,You are required to provide the stack.xml file ,If you have selected the expert mode then you need to provide the information about the shadow instance creation such as instance number and availability of reusable profiles, you also need to provide the number of ABAP, SQL, R3load processes for uptime and downtime processing .For migration scenarios you need to provide migration parameters, Migration key, target DB information, Target DB specific password etc. If you are using downtime-Optimized DMO ;you are required to provide the text file listing tables that will be migrated during uptime .Apart from input collection multiple checks are performed by check phase of SUM preparation roadmap .It checks the current system for required notes, open modification, inconsistencies between ABAP and DB dictionaries, SI consistency checks, ASU upgrade checks and other checks related to SAP S/4 HANA Conversion.
Preprocessing is where actual uptime shadow upgrade takes place. If you have selected downtime-optimized conversion then uptime migration and conversion of selective data also happens during preprocessing phase.
Execution phase is where Business downtime starts and shadow instance is stopped and merges with main instance, application data is migrated, table conversion happens, adapted to new structure and finally System is switched to new kernel. Reducing the runtime for execution phase is important to achieve the business downtime goal. Refer SAP Note 2351294 – S/4HANA System Conversion/Upgrade: Measures to reduce technical downtime
Post processing phase is last phase of SUM tool. At this point system comes back online and SUM tool Generate ABAP Loads and Run other cleanup jobs activities and SUM process is completed .
Custom Code Adaptation
After the Software Update Manager (SUM) has done the technical conversion, you can start adapting your custom code.You need to adapt any modifications and enhancements using the standard transactions SPDD, SPAU and SPAU_ENH.You need to fix any issues due to SAP S/4HANA simplifications.To find the issues, you use the ABAP Test Cockpit (ATC) and do a check run with the check variant S4HANA_READINESS locally in your converted system. If it is your SBX or DEV system , can activate the business functions switch or Import with the switchframwork transport if it is your PRD or QA systems.
S/4 Hana conversion follow-up activities
When you convert your system from SAP to SAP S/4HANA Server, you have to perform cross –application follow-up activities such as adapting Database extension to S/4 Hana , Adapting the user interface, output management , conversion of authorizations, SAP Fiori UX enablement etc . Apart from that you have to also perform application specific adaptation and follow-up activities for Finance, Credit management, HR, Order and contract management, Retail etc. as per Conversion Guide.
With this blog, this series is concluded . I hope you have got some good information about planning your next SAP S/4 Hana technical conversion. Pls comment for any queries or simply share details based on your conversion experience.
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