So, I've recently setup 2 Exchange 2010 with HA on all 3 typical roles. I know that I can setup 5 mailboxes on the standard version, and many more on enterprise. However, with the 50-60 users I have on there, I don't see why I should have more than one. Also, with the DAG group, it initially had one mailbox on each server, but instead of replicating both on both servers, I removed the one from the second server, and made a replication copy of the one from the first server instead. I now have only 1 mailbox replicated on both servers using DAG. My question is - why would I want to have more than 1 mailbox? Thanks, Ole

With 50-60 users I would have only one mailbox store as well - replicated for HA as you have done. ( you are referring to mailbox stores, yes?)

Thanks, and yes I am. Would you use more than one when the amount of users increase to balance the load and/or to keep the mailbox stores below a certain size? Thanks, Ole

Yes. I generally like the stores to be less than 100GB (50GB -75 GB) is perfect for me - and if they get larger than that, I start to think about spreading out the users. Why? Because if I need to reseed, a "smaller" store makes that process faster.

Thanks, I appreciate your answers. Last question: I guess a good way of doing that, is when the users mailboxes gets big, and the store huge, is to create "department mailbox stores" - sales, accounting, operation, etc. Once a new mailbox store has been created, will moving a group of users to the new mailbox store automatically move all their old mail, calendar, etc.? Thanks, Ole

Yes, everything in their mailbox will be moved to the new store. If you create new mailbox stores, you can always simply move mailboxes at random as well - w/o regard to their departments. It wont make difference , its all really up to you. If you spread the mailboxes out w/o consideration of their depts, then if one store is down, it wont affect everyone in that department.

Great. Thanks for your help. :)