SAP 7.40 Migration from single stack to SAP HA configuration - DB migration

[Former Member]

Hi all,

I'm handling a migration of a SAP 7.40 ABAP stack from a single instance to a clustered SAP 7.40 software HA solution.

It means moving from

1x DVEBMGS CI isntance

1x DB

to

1x clustered ASCS

2x clustered DB

2x ERS (on each cluster node)

1 PAS

1 AAS

My query is around database migration. The move is homogeneous (ORACLE/Linux to ORACLE/Linux) but with the ASCS being split out should I be using SAP tools to control database migration or is it still cool to just do an ORACLE backup/restore-to-target/recover process.   I would assume it is OK as I cannot see the ASCS split affecting database content, however I want to check with the community and see how others have handled this

and, if you know, what SAP officially support for this process

Thanks & regards,

Jamie AKA doonan_79

[willi_eimler · Accepted solution]

Hi Jamie,

your question is:

Do I have to use SAP tools to split the ASCS or can I use ORACLE backup/restore method into a new installed system with ASCS.

I did it with a sandbox system. I installed a new system with ASCS. Then I made a backup of a system without ASCS. And made a restore to the new installed system with ASCS. It worked.

In your migration path is no gateway service. I know everyone tells you gateway service is no SPOF (single point of failure) but the gateway service is often entered "hardcoded" for example sapgw00. I made the gateway service HA too.

Best regards

Willi Eimler

[Former Member · Accepted solution]

Thanks Willi - we looked at making a standalone GW HA too but have no need here as there aren't any active RFCs with registered programs requiring it. So we've just left the GWs on the PAS/AAS (obv the ASCS does not include one).

Cheers, jamie

[Sriram2009 · Accepted solution]

Hi

Could you check this SAP Note

1708600 - Inst. Gateway SAP Systems NetWeaver 7.1 and Higher

Regards

Sriram

[Former Member · Accepted solution]

Interestingly SAP recommend "You can move forward with your proposed plan of installing a blank NW 7.4 HA system, perfoming tests and then performing the database backup

/ restore. Please keep in mind that you need to follow the step by step instructions in the System Copy guide for the database specific procedure and this will require you to reinstall the PAS and AAS."

I can't see any reason for this - anyone out there see any reason for reinstalling PAS and AAS in this scenario? (I.e. after DB refresh of HA target from single-stack (non HA) source)?

[Reagan]

Install the SAP system with the Oracle database with the same SID on the target system.

Delete all the datafiles and restore the database from the source system. You will need to install the SAP license and also adapt the RFC's once the restore is done.

Regards

RB

[Former Member]

Hi Reagan,
Appreciate you taking the time to comment, but is that somehow different to what I suggested above?

Any comment re ASCS split also would be very much appreciated if you have a view there

Regards, Jamie

[Reagan]

Hello Jamie,

Why do you want to split the ASCS on the source system ?

You do not need to do that. The database is not using a system number.

You install a brand new system on the target server with the setup of your choice.

Once the installation has been completed, stop the SAP system and the database. Delete all the data files. Take a full backup on the source system and restore that on the target server.

Install a new license and also adapt the RFC's.

Regards

RB

[Former Member]

Thanks Reagan,

That is exactly my plan but I wanted to validate that with the community as I was getting push back from someone who believed this would affect the database. What I wanted was support for my assertion that this approach is correct. I have got it now both from SCN and from internal channels too.

Many thanks, Jamie

NB I'll update from helpful to correct once implemented

[JPReyes]

A bit late, but Yes.  The only thing you need is a backup of your source system. Then you can do a fresh install of the distributed environment.

Regards, Juan

[Former Member]

Clarification point.

I have read about the SPM (AKA SAPINST) option for "Split Off ASCS Instance from existing Primary Application Server Instance"

and I want to know if we need to do this pre-migration or if we can just install the split out instances on a new target and migrat the ORACLE database without ever using the "split" option.

[Former Member]

Clarification - Final Plan As it stands

So after much discussion I hope this final point either prompts comment, or helps others.

I've decided to run a full new installation (with ORACLE from SPM with NW Export Installation Media) and use this "clean" version for HA testing.

Then once that is complete I will drop the DB and run a homogeneous ORACLE migration from source using ORACLE recovery/archive log application to sync up.

I do not plan to split out the ASCS on the source first as through conversation with others I believe that this will have no impact whatsoever on the database that is the part which will be directly migrated.