Technical Articles
Monitoring Silent Data Migration (SDM_MON) – S/4HANA 1909 upgrade/conversion
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Is your customer planning for SAP S/4HANA Conversion to SAP S/4HANA 1909 or planning for Release Upgrade to S/4HANA 1909 or higher? then are you aware of Silent Data Migration? Do you know how to monitor Silent Data Migration? In this blog, I will describe how to monitor Silent Data Migration after a S/4HANA 1909 upgrade/conversion. |
Before beginning with this blog, if you are not familiar with Silent Data Migration, kindly check my earlier blog Silent Data Migration for S/4HANA 1909 Upgrade/Conversion to understand what is Silent Data Migration (SDM)? How is it enabled? Importance of Silent Data Migration user.
During the S/4HANA upgrade or conversion to target S/4HANA 1909 or higher, Silent Data Migration is used to migrate the application data while the business is on the target release without any disruption.
At the end of the SUM tool process, a background job will be scheduled once you execute the post-upgrade standard program BTCTRNS2, which releases suspended jobs. This job, SAP_SDM_EXECUTOR_ONLINE_MIGR, starts the execution of the SDMI classes during Business uptime. The job repository for Silent Data Migration can be observed using transaction SJOBREPO.
Monitoring the silent data migration is very important since you cannot continue with the next S/4HANA release upgrade until all SDMs are successfully completed. Hence, monitoring can help to identify failed SDM’s and eventually allow administrators to identify root cause, fix, and resume the failed migration. Also, monitoring SDM will help us to control resource utilization, managing the number of work processes utilized for the SDM guarantees a smooth data migration while the system is up and business is utilizing the system.
SDM is client dependent since the application data is usually client dependent. Hence, the SAP_SDM_EXECUTOR_ONLINE_MIGR background job will be triggered in each client. The first step in the monitoring is to make sure SAP_SDM_EXECUTOR_ONLINE_MIGR is scheduled & released in all the clients, after the upgrade.
Monitoring Silent Data Migrations
SDM_MON is T-code used for monitoring all SDMs. We can monitor the SDMs of all clients from the transaction SDM_MON.
ollowing is the initial screen of SDM_MON transaction before the program BTCTRANS2 is executed after the upgrade. The initial screen shows all migration classes, status in all clients, and whether they are qualified for online migration in the current release. You can switch between two different settings by selecting the following buttons (only one of them is active at a time)
- Show only qualified migration
- Show all migrations
Once background job SAP_SDM_EXECUTOR_ONLINE_MIGR is started, you will see the job’s status, for each client, in transaction SM37. The jobs will be executing by the SDM User the SUM tool created or which were created manually.
T-code -> SM37
T-code -> SDM_MON
Below is what the SDM_MON Silent data migration screen looks like when the SDMs are running. Those migrations in green status represents the SDM Migration is successfully finished in all clients, for that Silent Data Migration Class. The other status symbol indicates the migration class is waiting for a prerequisite to be fulfilled in one or more clients. 
If you would like to know what the status column signifies for each migration, a legend can be viewed by selecting the status and click F1 on the keyboard. A popup with information about each status symbol will appear.
In the following overview screen you can find the explanation of SDM Classes that are not qualified for migration in the current S/4HANA 1909 with status – Rhombus sign
button, it will display only relevant migrations which are valid for your current target release of S/4HANA. If you switch to Show Only Qualified Migrations view, the system will memorize your choice the next time you use transaction SDM_MON. The system will automatically load only the relevant migrations and the same settings previously set will be applied for all views.
to display the detailed progressing status of all migration classes in current client.
to display the detailed progressing status of all migration classes in all clients.
To display the complete status information about one specific migration class in all clients, select the respective migration class, and click on Migration Class in all clients.
Monitoring the Silent Data Migration logs
Step 1- Simply double click Migration class
Step 2 – You will automatically be redirected to the transaction SLG1 selection screen with the required fields having been auto-populated with the migration class’s values. Just enter the appropriate date and click on execute.
Step 3 –Double click on the log to see details
Records to be processed at first migration run – this is the number of migration records which the SDM finds at the very first attempt to run the migration. This number will never be updated afterward.
Records to be processed at start of migration run – this is the number of migration records found at the start of the current migration attempt.
Records to be processed at end of migration run – this counts the records found at the end of the current migration run. If all goes well, it should be zero.
Since in my example migration class CL_SDM_ACR_ACDOCA_ACRVALDAT does not have any records to process, I took another migration class CL_NGC_CORE_SDM_CLF_HDR as an example.
In the above example, the data objects are split into 43 packages by Parallelization Framework (PFW) for the Migration Class CL_NGC_CORE_SDM_CLF_HDR, with 4 parallel execution.
To check all the logs created during the execution of Silent Data Migration enter * at external ID in the SLG1 initial screen and click on the execute button.
By default, SAP_SDM_EXECUTOR_ONLINE_MIGR job runs every 30 minutes and picks up unfinished SDMI classes and re-triggers the SDM executor. Overall SAP_SDM_EXECUTOR_ONLINE_MIGR batch job only checks and triggers migration using PFW. But, the actual data migration is carried out by the MIGRATE_DATA method of an SDM Migration Class, using the dialog work process in the form of packages/portions.
Hypothetically the SDMs can run for days or even weeks based on the resource availability and amount of data to be migrated. During the event of a system crash or stop/start while the SDM’s are executing- SMD’s will automatically resume once the system is available again for the normal operations. SAP_SDM_EXECUTOR_ONLINE_MIGR job checks the status of failed SDM and restarts them again.
I hope this blogs will help to monitor the Silent Data Migration!!!
Please open a support ticket under component “BC-CCM-SDM” with SAP for any issue with Silent Data Migration.
Over all SDM were developed to optimized the technical downtime of S/4HANA sequential release upgrade(Examples S/4HANA 1809 to S/4HANA 1909), eventually to make ZDO possible for S/4HANA sequential release upgrades.
To further reduce technical downtime for an upgrade from S/4HANA 1809 FPS 01 to S/4HANA 1909 FPS 00 or FPS 01+ you may explore the option of Zero Downtime Option of SUM for SAP S/4HANA upgrades. Please check SAP Community blog for more details on Leveraging Zero Downtime Option of SUM for SAP S/4HANA update/upgrades Published by ZDO product manager Jens Fieger.
Additional information
Silent Data Migration: Silent Data Migration for S/4HANA 1909 Upgrade/Conversion
SAP Note 2907976 – Silent Data Migration (SDMI) – FAQ
SAP Note 2916801 – Silent Data Migration (SDMI) Configuration Options
SAP Note 2816875 – SDM Health Check with SolMan
SAP Note 2664638 – Create and assign SDMI User in a client
SAP Note 2821421 – SDM_USER: Allow creation without SAP_ALL profile
S/4HANA 1909 Upgrade Guide
SAP Help Portal Silent Data Migration Infrastructure (SDMI)
Zero Downtime Option of SUM for SAP S/4HANA 2707731 – Prerequisites and restrictions of Zero Downtime Option of SUM for SAP S/4HANA
Parishudh
IT Planning & Maintenance Optimization
Center of Expertise – Customer Success – Intelligent Delivery Group
SAP America Inc.
Hello Parishudh Reddy Marupurolu,
I have added your Information to my Blog - Upgrade to SAP S/4HANA 2020 - time to change
Best Regards Roland
Thank you
Hello,
Thank you for the blog, I went through the documentation, sap notes listed, etc … and I have very mixed feeling about this SDM feature. On the one hand, it is great that SAP provides ways to reduce downtime “for free” … on the other hand SDM raises a lot of unanswered questions.
What If I don’t want want to use this SDM feature in my upcoming upgrade S/41809 to S/42020 ? (As SDM S/4HANA1909 will be performed during downtime anyway)
Yes, I know that question is listed in the sap note 2907976 – Silent Data Migration (SDMI) – FAQ, but I am not sure I understand the answer : “SDMs must be executed and successfully completed before the next upgrade is started!” … What does that mean ?
If I understand it correctly, the Customer does not have much choice, there is no way to perform an upgrade like the way it was before. And by “before” , I mean that After the downtime was completed, I used to inform every line of business, that the technical upgrade was completed, and that they should proceed with their post- tasks and tests … and then open the flows (PO,BW, third party, etc …)
Now, after the technical downtime is finished, I still have to wait and monitor that SDM is successfully completed for the relevant application, before I could inform the relevant line of business and open the flows …Who wants to release a system if the data migration is not complete ? It is up to the Customer to take that risk ? I am not sure I see the advantages here.
And according to the same note, even after the upgrade, there is no guarantee that the application will switch to the new data model “Which option a particular application uses is not obvious.” That’s reassuring …
It is fantastic to provide Customers with more technical tools, but more guidance and pragmatism would be appreciated.
Hello Raoul,
let me comment in your main points:
"What If I don’t want want to use this SDM feature in my upcoming upgrade S/41809 to S/42020 ? (As SDM S/4HANA1909 will be performed during downtime anyway)"
In case of this upgrade path, you have only the choice for the Silent Data Migrations that come with SAP S/4HANA 2020. These can be either run after you finished the upgrade, or in case you plan for the next upgrade (maybe in 1-2 years) you can again let them run in downtime. If you would plan for a Zero Downtime upgrade like from SAP S/4HANA 2020 to a higher major release (c.f. SAP Note 2707731), all Silent Data Migrations would have to be completed prior the Zero Downtime upgrade.
"Now, after the technical downtime is finished, I still have to wait and monitor that SDM is successfully completed for the relevant application, before I could inform the relevant line of business and open the flows …Who wants to release a system if the data migration is not complete ?"
The main purpose of the Silent Data Migration is, that the system is fully functional already even though the Silent Data Migration hasn't been finished.
Last, let me tell you that we've taken your feedback back to our development teams. Thank you.
Best regards,
Jens
Product Management, SAP SE