Commvault has an Exchange public folder archiver and you are running it to get your public folder store size reduced.
If you are running Simpana 8.0 you should be aware that all written public Commvault documentation has told by fault that Exchange 2010 is suppported, but it wasn't. This wrong documenation was public until Oktober 2010 and has been removed in a "cloak-and-dagger operation" with my support call. We banged on this migration wall while moving from Exchange 2003 to 2010 and have been made by Commvault to wait for Simpana 9.0 SP1 that came available in mid January 2011. Because of so many bugs in the product we have been made waiting until mid May 2011 (SP2). You may be working with Exchange 2010 since November 2009 and you may have just waited for Exchange 2010 SP1 that has been released in June 2010 to get a more stable Exchange 2010 and to finish migration.