tuning a linux database for demantra 7.3.1

We are trying to tun our TEST environment prior to going live with production.  We run on Oracle unbreakable linux, database 11.2.0.1. 

We've followed the July 6th webinar on this subject.  In the list of required parameters it shows filesystemio_options=setall.  What value should we have for disk_asynch_io?  

We are running our first production sized loads and it seems it should be running faster, so we are trying to understand the relationship of all the parameters.

Thanks in advance for any help!