Background Information
- Ora9i
- Raw devices based storage
- Some DIM tables are large, in excess of 250 million rows
- A couple of DIM tables are very large, in excess of one billion rows
- All large and very large DIM tables are range partitioned
- Each large DIM table is sitting in its own private tablespace
- Each very large DIM table is sitting in its own private tablespace/s
- Small DIM tables are grouped in a couple of generic DIM tablespaces

Benefits of Having Private Tablespaces for Large and Very Large DIM Tables
- Allows for more control over physical I/O planning, monitoring & remediation
- Allows for physical vs. logical I/O crosscheck monitoring
- Allows for more control on backup/restore strategy
- Allows for specific blocksize leading to private/semiprivate buffer caching
- It looks cleaner, nicer, more elegant

Just my experience and what works for me