Tools for Migrating ECC on Oracle DB to HANA DB

What are tools available for Migration?

SAP has provided two tools for migration from ECC to HANA. One is traditional tool which is used for independent database migration using Export/Import method and second is Database Migration Option tool, which is known by its acronym as DMO tool.

Here, we will discuss both the tools but SAP recommends to use DMO tool because you have option to upgrade and migrate SAP system together which significantly reduces the time if done separately.

DMO tool can be used if your target system is SAP ASE (Sybase) or SAP HANA.

If there are lack of resources in your company you should use SAP ASE as it takes only 16-32GB to install high loaded system. However, if you are more focused in performance and speed, then you should always go with HANA database. The RAM requirement for HANA database will be twice the size of your database.

RAM = 2 X (Size of Database in HANA)

• Migration using DMO

Below I have shown the screen shot of SUM 2.0, you can select the required option if you need to upgrade your system along with migration.

To migrate the SAP System, you first need to check in Product Availability Matrix (PAM) whether it is feasible to migrate it using DMO tool, in most cases you have to upgrade the system to the latest because SAP HANA doesn’t support old version of SAP.

You need to check source versions on PAM in case you need to upgrade/migration simultaneously.

Below is the example

Source: SAP Netweaver 7.0, Oracle 11g, Kernel 7.21

Target: SAP Netweaver 7.5, HANA 1.0 SP12, Kernel 7.45

In the below screen shot you can see that to upgrade/migrate SAP system you first have to upgrade your Oracle database from 11g to 12c , because SAP NetWeaver 7.5 doesn’t support  11g

Strategy to upgrade/migrate system from oracle to HANA

• Feasibility – check in PAM that the system is upgradable else you need to upgrade the source system to a certain level, like in above example you have to upgrade your oracle database
• Requirement – In PAM you will get to know about release versions, to check the SPS level, use DMO guide for the SUM version you are using. The support packages you may need to upgrade will mostly be SAP_BASIS and SAP_ABAP.
• Planning – you need to prepare the target system for migration, install the SAP HANA on target system and also SAP HANA client on source system because you have to run SUM/DMO tool from source database
• Execution – use option migration when you run DMO

• Migration using SWPM

This procedure is independent of databases, you can run SWPM and select option export in source system then move all exported files to target system and then run SWPM on target system. Finally, you need to select the import option.

Below are the steps that need to be executed-

• In distributed scenario, this procedure needs to be run where database is installed. You need to run the pre-requisite in SWPM before export. To do so, select version of the SAP Netweaver – then select database –  select whether it is ABAP of JAVA – finally,  select the pre-requisite.
• Once prerequisite is completed, with the same navigation select Export AS ABAP system.
• When you export the system, it will create folder with the name AS ABAP. In this folder you will find STR files are located where actual data is stored.
• You must first install HANA database and then start SWPM on target system.
• Copy your exported file from source to target and do not change structure of the folders, it is better you use tar untar command instead of manual copy paste

• Use latest kernel which is available in SAP service marketplace
• It is recommended to use same version of SWPM to import which you have used for export in source system
• Start SWPM in the target system and select option import to Target system.
• Here SWPM will ask you three files

1. SAP HANA client – use latest version
2. SAP Kernel – use latest kernel version and download disp+work separately, it is recommended to use (n-1) version because sometimes latest kernel is not being tested properly.
3. Export file which is created during export

Advantages of DMO over Traditional Method SWPM

• You can directly migrate and upgrade in one process. Only one downtime is required
• SUM/DMO is an advanced tool, very less issues are seen in these as compared to SWPM
• You can monitor packets (migration files) in DMO, same option is not available in SWPM
• You can change processes runtime without any interruption, restart of shadow system is not required

General Issues encountered in the upgrade process

• High CPU utilization – Due to high CPU utilization on target system, your migration might get stuck and unnecessarily it will run 3-4 times longer than usual.

Solution – Do not increase R3load process to more than 3 times of your CPU

Below is calculation formula

Number of R3load = 3*CPU

• Off logging into HANA system – If parameter log_mode = normal then there will be huge log generated during migration process and in case you cannot provide extra space when logs will be growing then your system will be crashed, in this scenario you must run execution phase from scratch after restoring your system.

Solution – set parameter log_mode = overwrite

• Run reorg in oracle database before Upgrade – This is very important step if you have avoided this step then migration process can take longer time.

Solution – Goto transaction dbacockpit in SAP select top 50 tables and run reorg using BRtools.

• Table mismatch in execution phase –

It is always recommended for an SAP BW system to run SMIGR report in the source system, when you run SMIGR_CREATE_DDL, one sql file will be generated.

There is one step where DMO tool will ask you if you have SMIGR generated before, select yes and give path of the file.

Note – it is recommended to create SMIGR file just before starting of migration. It is better if you log out all users and then execute report in source system.

About the Author: Murtaza Nazmi is a certified SAP BASIS Consultant with 6+ years of experience. He has expertise in HANA Migration projects.
His experience comprises 4 end to end Implementations and two support projects. He has worked in different geographic locations like South East Asia, Europe and Middle East.
He likes watching games and follows English premier league.