Yesterday Microsoft released the Exchange 2013 version of the JetStress Tool.
The JetStress tool is used during deployment to verify the performance and stability of a disk subsystem prior to putting an Exchange 2013 server into production. JetStress can help verify disk performance by simulating Exchange disk Input/Output (I/O) load, it does so by simulating the Exchange database and log file loads produced by a specific number of users.
It is highly recommended to read the full documentation for JetStress before using the tool.
Download the tool here: http://www.microsoft.com/en-us/download/details.aspx?id=36849