Need help on migration

[Former Member]

Hi Folks,

we are planning to migrating existing production system with SAP on AIX OS and oracle database to HA Redhat linux cluster server and oracle DB.

I have few queries regrading this migration. Please can anyone help on this.

1) Once HA system built on RHEL cluster can we restore the archive logs from old production which is on AIX?

2) We are doing SAP export import method to build the HA system, So is it possible to apply archive logs?

3) Can we do data compression while exporting the data in source system?

Regards,

Shree

[stefan_koehler · Accepted solution]

Hi Shree,

i am kicking in as my name was mentioned here

>> 1) Once HA system built on RHEL cluster can we restore the archive logs from old production which is on AIX?

Depends on how you have taken the archive log backups. If you have not used RMAN and still got the archive logs in some third party backup tool, then yes you can restore them. However this does not make sense at all as archive logs can not be used for recovery in cross-endian scenarios like yours (AIX = big endian, Linux = little endian). The format is different.

>> 2) We are doing SAP export import method to build the HA system, So is it possible to apply archive logs?

No for two reasons. First the cross-endian scenario that i have mentioned before and second you get a completely new database on the Linux system if you use the SAP export/import method.

>> 3) Can we do data compression while exporting the data in source system?

The data itself is compressed by default with R3load, but i think you mean the Oracle index or advanced compression. And yes you can also enable the Oracle compression stuff, but this is done in the import phase, not in export phase.

>> Maybe Stefan Koehler can have better suggestions on this like using Oracle to Oracle

It all depends on your downtime requirements and the corresponding database size. However there is an advanced Oracle migration scenario called "Transportable Tablespace using Cross Platform Incremental Backup", which reduces the downtime to only a few minutes regardless the database size. This scenario was introduced for Exadata migrations only first, but luckily Oracle removed this restriction (more details can be found in MOS ID #1389592.1) and it works

Regards

Stefan

[Reagan · Accepted solution]

Stefan, Thanks for the reply.

Also the best option would be to move directly to Oracle 12c once it is fully supported by SAP.

2133079 - Oracle database 12c: Integration in SAP environment

I read on some article that from starting with Oracle 12c the database will be running under Oracle user and not under ora<SID> user.

[Former Member]

Hi Stefan and Reagan,

Thanks for the valuable information and the help.

Regards,

Shree

[Reagan]

>>1) Once HA system built on RHEL cluster can we restore the archive logs from old production which is on AIX?<<

Never tried to restore archived logs from between two systems on different OS. Even if it is possible I doubt whether SAP supports it. There is an Oracle document about heterogeneous configuration. Data Guard Support for Heterogeneous Primary and Physical Standbys in Same Data Guard Configuration (Doc ID 413484.1)

>>2) We are doing SAP export import method to build the HA system, So is it possible to apply archive logs?<<

If you are doing export/import then it is not possible to apply redo logs.

>>3) Can we do data compression while exporting the data in source system?<<

Yes, it is possible.

[Former Member]

Hi Reagan,

Thanks for the reply. Please can you explain why its not possible to restore the logs from old production system to HA system. it will be same database as source database only OS is changing.

Do we not have any option oracle to restore the logs.

Regards,

Shree

[Reagan]

Hello Shree

Again, I have only done R3load based system copies (migration) if there is a change in the OS and even if the DB stays the same but it looks like BR*Tools provides the functionality to do Heterogeneous system copies according to the information supplied in this SAP note

1003028 - Extended support for database copy in BR*Tools

Check the point 3. Enhanced support for heterogeneous database copies

But it does not say anything about the archive logs. I believe it should be possible ONLY if the systems have same Endian

Maybe can have better suggestions on this like using Oracle to Oracle

1508271 - Oracle Lifecycle Migration Service (formerly O2O/Triple-O)

Cheers

RB