I will detail here some notes made during OS/DB migration of a large SAP system.
I will be focusing on one key part – using a large PSAPTEMP tablespace vs using a smaller one (less h/w resources) and using unsorted exports for large tables.
I’m starting out with a viewpoint of going for a very large PSAPTEMP TS’ – especially if the resources for such are available and only temporarily needed.
However I also read that export times are longer – though index creation on the target take less time and data is better organised post import (giving better performance having essentially REORG’d the whole DB).
Also I will also be making some small reference to the export and import of our largest table. It doesn’t have the most rows – only 30 million (ish) – however it includes a BLOB field and itself takes up over 800 GB on it’s own. It has caused us difficulties in non-production migrations of this system – especially as the PL/SQL table splitter failed a few times until we changed the field we were splitting it on.
That’s it for now – I wanted to make a start so that I can continue this little diary later on……