DB2 Delete millions of row - slow performance

Hi,
DB2 9.7 fp 4 / Win 2008 / 6 CPU / 8GB RAM

DBSIZE around 800GB.

This is the first time we are deleting data using a java apps which deletes older than YY-MM-DD.
The java apps was develop by our developers and uses correct indexes (no table scan).

Out of 400 million rows from 8 tables, we need to delete around 100 million rows.
The deletion ran around 12 hours and deleted only 10 million rows. So, I had to kill the job in the middle.
I setup infinitive logs each 100 MB size. I can see now around 150 LOGS were archived.
How can i investigate its performance ? what are the areas i may need to tune / check ?
Please advise.
Thanks,