OK, here's the situation:

The "data warehouse" that our ERP provider sold us has evolved into more of
an operational data store.  We are in the process of developing a more
traditional star-schema data warehouse.  The ODS is getting quite large,
currently at 150 GB.  The server has 4 SAN drives (2 for data segments, 1 for
indexes and the last for log files and extract files used to load the
database).  My two data segments are currently at 65 GB each and the index
segment is 36 GB.  Based on requirements for a new project I have at least 18
GB of additional data that I'll have to load.

My question is, are there any file size/performance considerations as these
files continue to grow?  The largest of the most frequently hit tables is
15.5 million rows in 30 GB (I know, pretty big rows, but that's what we got
from the ERP provider).  

Performance of the database overall is acceptable as we've added serveral
covering indexes for our most common report requests.

Suggestions and comments are greatly appreciated.