duplicate NWDI

[Former Member]

Hello,

for customer AVL we are copying several system landscapes from one datacenter to another. Now we would need to test the copied system landscapes (i.e. the copied development systems in the new datacenter).

AVL also has got a NWDI instance, so we would need to copy it to the new datacenter. Unfortunately all SAP documentation is only speaking about MOVING a NWDI, and mentions that COPYING is not possible.

Excerpt from SAP note 877029:

IMPORTANT:

CBS and CMS do NOT support the COPY option. This means after the System

Copy migration was done you are not allowed to use the CBS and CMS in the

source system anymore. If the COPY option is selected only for DTR a COPY

is done, for CBS and CMS only a MOVE is done.

We need to build an interim NWDI in the new datacenter just for testing.

Currently we cannot move the NWDI to the new datacenter yet.

Is there any way to duplicate a NWDI just for testing purposes?

Regards

[Former Member · Accepted solution]

Hi,

As I understand the note, you should not use the "original" NWDI, when you didn't change the runtime systems in the "copied" one and changed the DTR/CMS/CBS accordingly. Meaning: you should not use 2 NWDI's towards the same runtime systems and/or CMS/CBS services.

As your copied NWDI is a test environment, that will be thrown away, I do not forsee big problems. When the new datacenter comes to live, you will use the "move" option for your NWDI migration.

Futhermore you should make sure your developers do NOT connect to the copied NWDI AND to the original NWDI from the same development machine as the track info on those machines can not differentiate between the two.

I think you can copy the NWDI as long you can garantee the landscapes in two datacenters will never connect to each other on any level (from one datacenter to the other i mean).

Hope this helps.

Regards,

Alain.

[Former Member · Accepted solution]

Hi Alain,

Not sure but I have the similar question again.

We are doing data centre transition & as part of that we are building trail migrations to build production like landscape to do performance testing/resolve any issues which might arise during the export process.

NWDI is one of the system.

Can you please confirm if we export our NWDI using MOVE method & build a system with same name in Isolated env just to test the export/import process will cause issues to real system. if you use MOVE does it changes anything in the source system?

What if we create a clone of our NWDI system in isolated env & then run MOVE against it to take a export using move method.

Looking forward to your response.

Cheers!

Ajay

[former_member189220 · Accepted solution]

Hello,

Please refer to this document:

NWDI/JDI System Copy Migration

http://www.sdn.sap.com/irj/scn/go/portal/prtroot/docs/library/uuid/70ee5ab2-8d7a-2c10-d88b-dbe2fdf66...

Interesting points:

How can a System Copy be done? How does the System Copy Tool work?(p.4)

NWDI/JDI and System Copy, how does it work?(p.5)

Regards

[Former Member · Accepted solution]

Hi Milen,

Thanks for the link to document. But I have already gone through the document. The document seems to be ambiguous & not very clear.

Can you answer the below questions:

What happens to source system when we use Move method.

The book says:

After the System Copy is done you are not allowed to use the NWDI/JDI on the source system any more. If you continue to use the source system you’ll ruin data un-repairable!

What happens when we use the move method to export the system & doesn't want to build new system due to any reason. Does this mean that we cant start source system back.

Or Does it mean that we should have only one NWDI system running after move. Either the source itself or target.

Cheers!

Ajay

[former_member189220 · Accepted solution]

Hello,

Nothing happens on the source system.

However if

you have used MOVE option,

and

the source and the target system work in parallel (or by some unfortunate coincidence start communicating with each other) then you will face problems because:

"Some applications (e.g. DTR) rely on entities that have globally unique IDs. If the database content is simply copied from the source to the target system all entities of the source system exists after the copy with the same ID also in the target system. These entities can now be concurrently modified in both the systems which leads to the situation that entities are indeed different although they have the same ID. This can cause severe errors and inconsistencies in the application. E.g. in DTR there could be two versions with the same ID but with different contents." (p4. from the same guide)

Please also refer to section

"The System Copy options 'MOVE' and 'COPY'" (p11)

Regards

[Former Member · Accepted solution]

Hi,

Thanks for response.

So till the time the system cant talk to each other & other systems in landscape doesn't not talk to new copy there are absolutely no issues.

Issue only arises when by mistake both NWDI system talk to each other or other system in landscape connect to both source NWDI system & new copy of NWDI.

Regards,

Ajay