We are planning to migrate from Exchange 2003 to Exchange 2007. We currently have 5 storage groups with 4 mailbox databases on 2 servers. Following Microsoft's recommendation, we are moving to 20 storage groups with 1 mailbox database each on a cluster managed server (CMS).
Realizing that Exchange 2003 has a 50GB recommended mailbox database limit & Exchange 2007 has a 200GB recommended mailbox database limit, we want to make the new mailbox databases no bigger than 100GB each to accommodate future growth.
Our current largest mailbox database on Exchange 2003 is 450GB and a couple more are over 100GB. We are trying to come up with a strategy on how to divide up the mailbox databases when we move them to Exchange 2007. Our largest individual mailbox within a current mail database is 12GB and we have over 300 users with mailboxes larger than 1GB.
Is it better to group all the big mailbox users in their own mailbox databases (keeping them under 100GB) or is it better to mix them in with regular users?
We currently have no mailbox policies in place, we hope to implement them in the near future pending very slow management approval but the policies will not be in place prior to the Exchange 2007 migration. We MAY have 2 policies, one for very large mailbox users and one for regular users that has a limit of 350GB per mailbox.