I have an extremely large, crowded Exchange 2007 server running all (3) Exchange roles (CAS, Hub-Transport, Mailbox). I am migrating to a distributed Exchange 2010 environment with multiple Mailbox servers, and dedicated servers for each of CAS / Hub-Transport.
At our first migration attempt of a batch of 10 users, the server had big issues after the move with email delivery. Delays of inbound email to users on the original Exchange 2007 server, delays of outbound email from users on the original Exchange 2007 server, BUT the users migrated to the new Exchange 2010 system experienced NO issues at all.
Inbound email from the firewall still arrives at the original Exchange 2007 Hub Transport server and that has not changed...so it does not make sense that after the migration all users still on the 2007 system were having delay issues and users on the Exchange 2010 server were NOT. I did notice that the pre-submission queue database was quite large at the time (3+GB). A reboot of the Exchange 2007 server eventually solved all of these delay issues, restarting individual Exchange services did not (Transport service, info store, IIS in general).
What I wanted to do to prevent this was to create a dedicated Exchange 2007 Hub-Transport server (as a VM) and bridgehead that to be the server that does the moving of messages to the Exchange 2010 systems. How can I do this? I feel like this would alleviate the load and let us migrate the balance of the users (almost 1000 users in total) without affecting the existing services of the already overloaded server.
Does anyone have any insight as to how this can be completed?