DB2 integration is quite tricky. Converting a notes database to DB2 is simple. But the impacts can be horrible :-)
I tried it with a simple database, no problem.
A more advanced database with 350 views didn't work as expected. I was able to open the database but some views won't display.
I got a "index is corrupt...." message when I've tried to open it. Compact, fixup, updall nothing worked. I tried it with 3 different copies, all with the same result.
Either google nor the notes forum had a solution for that problem. Tomorrow I have to test it with some other databases...