Good morning Prashant,
This isn't really an OS migration, just an OS upgrade, which you need to do anyway. For system copy purposes, it's much the same from Windows 2003 to 2008 or 2012, etc (except, of course, for ensuring that your OS, DBMS, and NetWeaver versions are all compatible per the PAM). So, you can definitely use the "Database-Specific System Copy" procedure as described in the "ABAP+Java" System Copy Guide.
This means you will basically use database backup/restore for the ABAP/database portion of the system copy, and then use export/import for the Java portion. You could use pure "database-independent" procedures for the entire thing, but this typically takes much longer and involves more downtime on the production/source system. However, if you also want to do something like distribute your database across a larger number of disks, then this might be the opportunity to do that. However, that's a different goal and a different discussion.
I understand you're trying to drop the Java portion of your dual-stack system. However, you must either do a full dual-stack system copy, or you must do a dual-stack split directly in production before doing the copy. As I don't recommend performing a critical operation like a dual-stack split in production without testing it first in DEV and QAS, I suggest the first option, which is to do a full dual-stack system copy to create new, consistent DEV and QAS systems. Then you can do the dual-stack split on DEV, then QAS, then finally PRD, in a safe, consistent, tested manner.
Simply doing a system copy of the database and leaving the Java export behind is not a recommended approach for splitting a dual-stack system. This exposes you to the potential for numerous inconsistencies in your target system. I realize this is what your predecessor did to create your current ABAP-only DEV and QAS systems, but those systems still have a Java schema in the database, as you pointed out, and while they could no doubt be cleaned up, it's much safer to use the SAP-supported method of the dual-stack split tool.
So, to address your questions directly:
- I'm not an Oracle expert (I work with SQL Server on Windows), but I am a Windows expert (or at least, I work in Windows a lot). I am quite sure that an Oracle backup taken on Windows 2003 can be restored on Windows 2008 without any issue. What will matter here is the version of Oracle, more than the version of Windows.
- You won't be using the R3load method for the ABAP schema, but you will be using it for the Java schema, even though your Java schema is essentially empty. This is the best way to ensure consistency in the target system. The Java system export and import doesn't take very long compared to exporting an ABAP system. The SWPM System Copy tool will walk you through the procedure when you choose "database-dependent dual-stack" as your options.
- Once the system copy is complete, you can use Dual Stack Split tool to split off the Java schema, and then either eliminate, reinstall, or use the resulting separated Java system as you see best.
- You already pointed out that the old, deprecated system copy tool does not support Oracle 11g, and the current SWPM tool doesn't support Windows 2003 (are you sure about this? I thought it did, but I'm not certain, so will go with your findings). So, I recommend installing a new system with Windows 2008 or 2012, then using SWPM to copy onto that. Windows 2003 is running out of support anyway, so you will need to do this very soon regardless. Might as well be now.
Regards,
Matt