So Microsoft has simple, standard, large, and complex Exchange 2007 environment deployment scheme. We have a simple Exchange deployment. I was wondering what's the largest have you guys deployed in Exchange and what the difficulties that you guys ran into. Thanks.

Hi I think the difficulties always is coexistence and migration, doesn't depend SOO much on the size, of course there are different scenarios if it's a single server solution or a full HA/Site resiliency solution. But it's always complex to have a long period of coexistence between legacy systems and a new one.. Planning and information flow to managers and end-users is the key to success :) Jonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

depends what's big Hundreds of thousands of users raking up a couple of racks in a data centre (hopefully replicated) or 10,000 users with 500 servers spread all over the world due to bad network connections and decentralized IT departments. Here's a case study for the US Army: 1.2 million employees (thought not all with an Exchange mailbox.) http://www.microsoft.com/casestudies/Case_Study_Detail.aspx?CaseStudyID=4000000807

I have been consulted on a number of seven figure mailbox deployments. As for the rest (difficulties) - that is what clients hire me for. Simon. Simon Butler, Exchange MVP Blog | Exchange Resources

I'm seeing fewer and fewer Exchange 2007 deployments as time moves on. Most of my current projects are Exchange 2010. The largest current Exchange 2007 project I have is 700K seats. J

Why do you think customers are going right to Exchange 2010? Besides DAG, what are the key points of 2010 that you have seen so far?

Because of storage cost savings, think thats the key point And better HA/failoverJonas Andersson MCTS: Microsoft Exchange Server 2007/2010 | MCITP: EMA 2007/2010 | MCSE/MCSA Blog: http://www.testlabs.se/blog

How hard is it to deploy a UM on both Exchange 2007 or 2010? I have not seen this work in a production environment. Thanks.

I'm seeing fewer and fewer Exchange 2007 deployments as time moves on. Most of my current projects are Exchange 2010. The largest current Exchange 2007 project I have is 700K seats. J Some of the smallest deployments have given me the most headaches! :)Principal Consultant, Silversands | www.silversands.co.uk | www.msexchange.org/neil_hobson

Neil, Can you provide a sample on where you had difficulty with small deployments. What about UM? Thanks.