I personally did not first discuss about an exchange environment, you did. Second, your experience with exchange servers might be with small to medium corporations who deal with a couple of hundred employees. As I personally have experience with multiple large corporations having more than 100 thousand employees, the exchange server only allows a couple of hundred MBs on the server itself, while the "rest" needs to be moved to the PSTs. Further, I understand the OPs question which is why I never mentioned exchange before you. I am sure the OP appreciates the help put towards helping him find that PST and I am definitely sure he appreciates having multiple option in hand in case one fails...