OS/DB Migration - MSSQL to Oracle

[Former Member]

Hi all,

We're planning to migrate ECC 6 as follow:

Source system:

OS: Win2003 server, 64bit, Enterprise edition

DB: MSSQL server 2005

Target system:

OS: RH Linux

DB Oracle 11g

Does anyone have any experience with this kind of migration?

I'm especially interested in disk-space requirements.

Regards,

Ami.

[former_member185954]

Hello Ami,

What diskspace requirements are you concerned about?

- The target database diskspace requirements?

- Temporary Storage required during Export and Import activities to store the Export dump?

A rough way to determine this is to export the MSSL Database using Migration Monitor process to a temporary location.

Normally a non unicode MSSQL database is compressed by a factor of 8 to 10, so if your database is 80 GB, the export dump might be upto 10GB, so you might want to allocate a temporary space of 15GB.

Further when you import this export into the target and the target is Oracle, you might need around 12 times the size of the dump.

if you have a 10GB export dump, the oracle database you are looking at is around 120GB.

While running import, the SAPINST tool allows you to configure the individual tablespaces and sapdata sizing. So you can take your rough number (for e.g. over here 120GB) add 20% contigency to this and configure your sapdata(s) as per your needs (your needs means depending how much performance you need from your server) and then during import allocate the tablespaces as per the sapdata sizes.

Again, as Markus has already informed earlier - This needs to be done by a SAP Certified Migration consultation, the example I gave above is just give you a rough idea.

Regards,

Siddhesh

[former_member189725]

Let me answer your query on disk space requirements .

If you do a sorted unload of the data (data is read in the order of primary key), then a reorganization of data leads to shrinking of db size on the target . An unsorted unload will not reorg your target db. This sorted or unsorted unload is db dependent . For Example Maxdb does not support unsorted unload..

If you use DB2 LUW 9.x , the row compression feature allows your target db to shrink by atleast 30-40% depending on the compression dictionary . The compression dictionary has a better quality if data is unloaded unsorted in the source db.

For unicode conversions , there will be increase in disk requirement depending on the language installed as the characters may take up 1 or multiple bytes depending on the unicode transformation format (UTF) used. SAP generally uses UTF-8 .

Hope I could give some idea on your query.

Regards

Ratnajit

[markus_doehr2]

> Does anyone have any experience with this kind of migration?

> I'm especially interested in disk-space requirements.

A heterogeneous migration requires a certified migration consultant on-site, otherwise you'll loose support from SAP for problems during the migration and you also loose support for the target system (see http://service.sap.com/osdbmigration --> FAQ).

A migration consultant can tell you out of his experience what kind of problems you'll face when doing such a migration.

Markus