Hello there. Let me explain better: I belong to an Exchange 2003 Admin Team which supports a large company (our customer) with about 2000 users per server. Recently this company has decided to increment the mailbox quota for its users in about 400 MB. So far so good, but there are also a lot of users that have a custom mailbox quota that reach 1 GB and more. The amount of these "custom quota" users keeps growing every day, making us go through a hard time with the space and server performance. Bottom line is that we are looking for a Microsoft recommendation or any kind of document which advice to keep a low quota size for mailboxes to prevent bad server performance. This document (if there is one) will definitely support our recommendations to the customer. Thanks a lot in advance.

Take a look at these. http://msexchangeteam.com/archive/2005/03/14/395229.aspx http://support.microsoft.com/default.aspx?scid=kb;EN-US;905803 Are you actually having performance issues with this or is just a management nightmare? Mark Morowczynski|MCT| MCSE 2003:Messaging, Security|MCITP:ES, SA,EA|MCTS:Windows Mobile Admin|Security+|http://almostdailytech.com

Refer below thread http://social.technet.microsoft.com/Forums/en-US/exchangesvradmin/thread/c77068fd-67b2-4288-a8d6-0214a9c67a4b Vinod |CCNA|MCSE 2003 +Messaging|MCTS|ITIL V3|

Hi,Please check whether the below article can help you:http://blogs.technet.com/danielkenyon-smith/archive/2009/01/16/planning-mailbox-quotas-part-i.aspxThanksAllen