DMO and SAP HANA log mode considerations
You are working on a migration scenario to SAP HANA database using Software Update Manager (SUM) with its Database Migration Option (DMO). You wonder which SAP HANA log mode the tool is using during the migration.
The available log modes of SAP HANA database are explained in the documentation, for example using the following link https://help.sap.com/viewer/6b94445c94ae495c83a19646e7c3fd56/2.0.05/en-US/c486a0a3bb571014ab46c0633224f02f.html. Relevant statements are:
- SAP HANA can run either in log mode normal or overwrite.
- After installation, SAP HANA temporarily runs in log mode overwrite.
- Log mode normal is recommended to provide support for point-in-time recovery.
New: with SUM 2.0 SP 14 (and higher), SUM will set the log mode to overwrite before the migration happens. At the end of the DMO procedure, SUM will set the mode to normal. You will then create the (first) backup for the SAP HANA database, as listed in section Follow-Up Activities of the DMO guide:
This is now aligned with the behavior of Software Provisioning Manager (SWPM), which asks you to create a full database backup as well (see https://help.sap.com/viewer/3741bfe0345f4892ae190ee7cfc53d4c/CURRENT_VERSION_SWPM20/en-US/b1d3cf2bcb8048fbad959ec69324bfb3.html).
The previous behavior of the tool was different. Up to SUM 2.0 SP 13, when you started the DMO run, SUM didn’t change the log mode. If there was no database backup taken for SAP HANA, the database has treated this as mode overwrite. At the end of the DMO run, you follow the SUM recommendations and created a full backup. After this first backup, the SAP HANA database switched to normal mode.
Boris Rubarth, Product Management SAP SE