Efforts in Technical Migration

This is a follow up article of SAP System Migration , please make sure that you have read the previous blogs or have the understanding of those topics :-






In the Source System we check first the components that needs to be certain that they can be migrated especially JAVA Based Components . To Point out these information need to be checked on Source System:

1. SAP Products Installed
2. Version of Installed Products (Enhancement Package, Support Package , Kernel Version)
3. Fully understand the System Landscape 
4. Number of System to migrated and are in PROD state.
5. System Migration order and time schedule  of the migration needed by customer.
6. Maximum System Downtimes for migration purposes.
7. System Access in case of hosting environments.
8. Operating System and Database System , as we have dependencies based on it.

Technical points needs to be checked at :-

1. Current Hardware (RAM, CPUs, disk sub system)
2. Size of Source Database (compressed / uncompressed)
3. Free local disk space for unloading the database. 
4. Largest tables and indexes.
5. Code page used. Character Encoding
6. Tables in ABAP Dictionary but not in DB or the reverse.
7. External Files and interfaces (spool, archives, logs, transport files and interface)
8. Procedure for transporting the dump files from the source to target system.

Number of Export process required is decided by :-

1. Number of CPUs
2. Information about the I/O subsystem

Time that will be needed for migration is decided by :-

1. Database Size
2. Size of largest table (influence export significantly)

As we have understood in previous blogs that we need to perform test migration first that will require 10%-15% of the uncompressed source database size as export file system free space.

Apart from Source System we would also require information about the target system , Obviously!

Things to check :-

1. Target Hardware (RAM, CPU, Disk Sub System)
2. Target OS and DB version that is planned.
3. Date of Hardware Availability or Delivery.

How the Migration  actually goes on :-

[ TEST ]

1. Install migration tools and prepare the source system. (Example : for ABAP R3LOAD, R3LDCTL, R3SZCHK for JAVA JLOAD, JSIZECHECK)

2. Export data from source system.

3. Install the SAP product and the database software on target system (on target perform the installation).

4. Transport / Share the data export to the target system (data transfer from source to target).

5. Create an empty target database.

6. Load the data export to the database (in step 2 we unloaded the data or made data ready for transport from source to target , in step 4 we shared from source to target, in this step the data from source db is loaded to our target db)

7. Complete the installation and perform the follow up tasks.

8.  Configure the test environment.

9. Extensively test the migrated system.

[FINAL]

1. Create a cut-over plan (While planning cutover plan include active checklist and time schedule , also plenty of reserve time )

2. Perform the migration

3. Perform the follow-up task

4. Check the system (It is not required to repeat all the application test and checks that were already done in TEST phase . It should be reduced to absolute necessary)

5. Run a backup

6. Start production work

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