Could you help me to find answer for following question please? I have customer which policy doesn’t allow deleting any e-mails from mailboxes so they are really huge (top one has 25GB). Currently he has Exchange 2003 and many PST files. I’m thinking about offering him Exchange 2010 with personal archiving feature and migrate all .pst to database. However I tried to find any document which will tell me what reasonable size of mailbox is. Let say I don’t worry about storage capacity and any security issues. I found (http://www.mailmeter.com/WhitePapers/E2010-Archiving-Waterford.pdf) that reasonable size of main mailbox is 10GB as well as archive one and it shouldn’t be too much bigger. If it is the case I’m not able to use Exchange 2010 for this company. Could you advice?

Hi,It mainly depends on your organization configuration and hardware performance.You should run Exchange 2010 Mailbox Server Role Requirements Calculator first.http://msexchangeteam.com/archive/2009/11/09/453117.aspxFrank Wang

Many thanks for your reply. As far as I noticed there is no information about limits for single mailbox on documents in the link. I just wonder if I can have mailboxes let say 10GB for main and 50GB for PA. Or even 60GB for main. Will it work? What problems may I have? Any possibility of corruption or data lose?