Is there any reduction in IOPS?
Yes, another huge 70% reduction in IOPS with Exchange Server 2010. This is on top of the 70% IOPS reduction from Exchange Server 2007.
What does this mean for my storage requirements?
The Exchange 2007 IOPS reduction meant you could leverage Direct Attach SAS disk storage cabinets vs. traditional SAN for Exchange 2003.
With the additional Exchange Server 2010 IOPS reduction, this means you can deploy even a lower cost storage solution such as Direct Attach with SATA disks and still maintain excellent performance.
If you begin to use some of the triple database replication copy scenarios for database high availability, you could even begin to use JBOD SATA (RAID-less) storage.
The idea behind this logic is since you are maintaining 3+ copies of your database spread over multiple JBOD SATA disks the value of using RAID disk sets adds little value or unnecessary additional performance.
Are there true cost savings with using DAS SATA or JBOD SATA?
With the samples below, you can see with a 2GB mailbox using DAS with SATA drives you can drop the server/storage capex by 38% vs. DAS with SAS drives!
Here is a sample with High availability, you can see a 75% reduction in capex vs. Exchange 2007 when using Database Access Groups (new term for Exchange 2010 high availability) with JBOD SATA storage.
Note: These are preliminary performance and cost figures, and more detailed information will be available when Exchange 2010 launches.