Exchange 2010 Mailbox Server Reinstall

To directly answer your question, yes the Exchange config for the server will remain as long as the newly re-installed server has the exact same fully-qualified name as it originally had. All of the config settings for an Exchange 2007 and later server are stored in AD. So when you run setup Setup.exe with the /m:RecoverServer switch

Setup.exe /m:RecoverServer

then the Exchange installer will look into AD and get the previous configurations for the server and set this new instance up in the same way. You just have to make sure that the names are identical.

As for backing up databases and all, remember that you can move a mailbox database to another mailbox server and keep it active/online while this server is unavailable. So do that, in a big way. If you plan your database moves right (or, even better, have a DAG), and if you're using a good load balancer for your CAS roles, you can actually loose an entire Exchange server with no impact to the end users.

If this is your first time rolling through an Exchange server like this, then I recommend hitting the Oracle of Google for some step-by examples or videos. I just saw these in a quick search, they have good info but depending on your comfort level you may want more/less:

• http://ripusudan.wordpress.com/2012/10/09/how-to-customize-ms-office-2010-installation-using-oct/
• http://www.exchange2010.com/2011/06/setupcom-mrecoverserver-when-server-is.html
• or straight from the horse's mouth http://technet.microsoft.com/en-us/library/dd876880(v=exchg.150).aspx