I am planning on deploying Exchange 2010 in my environment and am trying to use the Exchange storage calculator to define what I need to have for hardware to replace our Exchange 2007 environment. I am having a heck of a time trying to figure out what to put in where to match what we have currently in our Exchange 2007 environment. Here is our Exchange 2007 setup: Three CCR clusters hosting three mailbox servers with each of them having 28 databases. 7000 users are spread evenly across the three servers. We have three SCR targets with 24hr lagged copies for the CCR clusters. Also have two hubs and two CAS. Our active servers are in one building and our passive servers are in another building (and lagged copies in another). The DAG environment needs to mirror this type of setup. Can someone help me put in the values in the calculator or just tell me what I should have for servers? Thanks for any guidance that can be provided

Here's one suggestion, there are others... 1. You can have a DAG group which has 3 databases across the 3 physical sites 2. Ideally you should have at least 2 HUB's and CAS's role per AD sites, which I assume your 3 physical sites represents. If yes, then maybe combine these roles on a server and leave the MBX seperate (DAG Member) or have them on there too. Think about your server spec before you do this. Use the Exch calculator to help you. 3. You might want to consider a CAS Array for each AD site. 4. Configure your replaylagtime and truncationlagtime for your database copies.Sukh

Thanks Sukh, I will configure the sizer with these options.