If you lose only a single Exchange server, then no. You cannot lose a message.
Here is a discussion about shadow redundancy, compared between Exchange 2010 and 2013. http://technet.microsoft.com/en-us/library/dd351027(v=exchg.150).aspx From: [email protected] [mailto:[email protected]] On Behalf Of Connolly, Peter Sent: Tuesday, October 22, 2013 3:23 PM To: [email protected] Subject: [Exchange] can Exchange 2010 lose mail through HUB server? All, 6 CAS/HUB servers, CAS Array, hardware load balanced, 6 mailbox servers in a DAG. We mirror the LUNS for the logs and queue on the CAS/HUB servers. I was asked by a manager if it was possible to lose a piece of mail in our design. So for instance if a message reached a HUB server, and the server crashed (say a complete loss...) before the message could be sent to a `mailbox server, is that message lost irretrievably? Will the originating mail server in this case receive an NDR? Thanks in advance, Peter
