I need to make a correction. I ve been aware of the fact that Exchange 2007 Standard Edition which is part of both SBS 2008 and EBS 2008 has an unlimited mail store size. Now I ve also been aware of the fact that Exchange 2007 Standard Edition can have up to 5 Storage Groups with up to 5 Mailbox Stores in each Storage Group. Further more each Mailbox Store can be up to 16TB in size. Now the bit where I have been incorrect is that I ve stated that you can have 5 Mailbox Stores in EACH of the 5 Storage Groups – therefore 5 x 5 x 16TB of mail. This is factually incorrect.
What you can have is UP TO 5 Storage Groups and UP TO 5 Mailbox Stores in each, however you can only have a MAXIMUM of 5 Mailbox Stores on Exchange 2007 Standard Edition. This means your maximum is 5 x 16TB or 80TB of mail storage in total. Here s a link to the MS site that more clearly states this.
Sorry for the confusion for the people I ve told the wrong thing to!
Further more, the default limit on Exchange 2007 Standard Edition and therefore SBS 2008 and EBS 2008 for the mail store is NOT unlimited that would be dangerous. It s actually 50GB per mailbox store. To increase or remove the limit you need to modify the registry for each of the mailbox stores concerned. This link here refers to Exchange 2003 but the same applies to Exchange 2007 Standard Edition too
Now that I ve gotten that out of the way, I ll answer the next question of WHY would I want to have multiple mailbox stores and multiple storage groups? For that I ll put together a post later this week.