Hi, We are currently working on replacing our IMAP mail system with Exchange Server, we have 30,000 users on our system of which about 5000 login concurrently at any one time. Our biggest challenge is to select which version of Exchange to use. Should we use 2003 which is tried and tested in the knowledge we will have to upgrade the whole system in a year or two years time. Or do we risk putting our users on Exchange 2007 and hope for the best? The service has to be fully deployed in September 2007, and I'm dubious about the stability of a new product from Microsoft until the first service pack which I don't have the release date for yet. Has anyone got any advice about which product we should go with? Or experiences of a similar size user base on Exchange 2007? Thanks Dave

There's no easy answer to that question, given all the variables that go into such a decision. Some thoughts that immediately come to mind:1. For 30,000 users, given a relatively standard disk i/o profile, you may find that the amount of $$$ you save on server hardware more than justifies migration to Exchange 2007, compared to 2003, given the scalability of 2007 and the 64bit operating system. 2. What other services need to be layered atop exchange, and will they be supported in 2007 in your implementation time frame?3. The existence or not of the 1st service pack for a Microsoft product, IMHO, isn't a great predictor of a product's reliability. I've seen, on both the OS and application side, bugs both squashed and created by service packs. What mitigates the risk in these cases is an architecture that lessens the impact of failures, a premier support contract, and an implementation schedule that hopefully allows you to sort out the major issues before they affect 30,000 people.

Hi BrianThanks for replying, responses to your comments follow1. For 30,000 users, given a relatively standard disk i/o profile, you may find that the amount of $$$ you save on server hardware more than justifies migration to Exchange 2007, compared to 2003, given the scalability of 2007 and the 64bit operating system. I agree that we may be able to reduce the amount of mailbox servers with Exchange 2007, but as we are attempting to put in a fully redundant system it would mean we require 2 transport servers and 2 client access systems too. Or would the transport servers be better placed on mailbox servers as an additional role? As our schedule is so tight we have already had to commit to expanding our EMC SANs to the next storage processor up (CX3-40) and add 7-8 trays to each. The project is very high profile and needs to be a success and that will be measured by uptime, money is less of an issue. If it where you which would you pick? 2. What other services need to be layered atop exchange, and will they be supported in 2007 in your implementation time frame? We are planning to deploy EMCs email extender and services for Blackberry both don't support 2007 at present, we are happy for these to be pushed back and implemented later. They are facilities we do not have at present so the majority of end users will not miss them. 3. The existence or not of the 1st service pack for a Microsoft product, IMHO, isn't a great predictor of a product's reliability. I've seen, on both the OS and application side, bugs both squashed and created by service packs. What mitigates the risk in these cases is an architecture that lessens the impact of failures, a premier support contract, and an implementation schedule that hopefully allows you to sort out the major issues before they affect 30,000 people. Good point, I still remember the headaches Service pack 2 for Windows XP caused when it was released. Unfortunately our schedule is very tight, the current plan is to make the decision early next year as to which platform to go with. We are getting some consultants in to assist but I think they will push us down the 2007 route for the kudos for there own business. Have you heard of any sizable sites implementing Exchange 2007 other than Microsoft? Thanks Dave

re: additional servers requiredYou're going to be adding these, regardless of which version of Exchange you pick. The CAS and H/T servers in Exchange 2007 are evolutions of OWA servers and bridgehead servers in 2003. Especially for the mail flow of 30,000 users, I imagine you're going to have some dedicated bridgehead servers for spam and virus filtering.re: other large installations running exchange 2007?Talk to your Microsoft account manager for additional references. They've had the Exchange 2007 rapid deployment program running for several months now, so they should have some non-msft references for you to talk to. Also, push for some Microsoft Consulting Services involvement, I trust 3rd party consultants as far as I could throw them.

Have you gottent EMC Email Extender to work in 2007 ? We are having alot of problems getting it fully functional. It also seems to drag down the performance of the client. Not having much luck with EMC .. There seems to be only one guy in their support team that knows how to use this product ? Anyhelp would be greatly appreciated ... Rob