This solution brief provides information on the HP P4500 G2 60TB MDL SAS SAN solution hosting Microsoft® Exchange Server 2010, based on the Microsoft Exchange Solution Reviewed Program (ESRP) – Storage program*. The performance results and best practices outlined in this paper provide tested guidelines for configuring a five node HP P4500 G2 12TB MDL SAS Storage Systems (AX703A) for use with Exchange Server 2010 in a 4,200 user environment.
In Exchange 2010, Microsoft made improvements that add new options to the menu of storage choices. Exchange 2010 delivers up to a 50% reduction in disk IO from Exchange 2007 levels, which means that more disk types meet the minimum performance required to run Exchange, driving down storage costs. Prior to Exchange 2010 HP only recommended enterprise class drives when sizing for Exchange environments. With the reduction in disk IO, HP can now recommend both 15k RPM SAS and 7.2k RPM MDL SAS, for different Exchange requirements.
Find here the whitepaper.