EXCHANGE INFRASTRUCTURE AND PLANNING
Hi
In this article series, I will try to explain how we can move into an Exchange 2007 organisation from an Exchange 2003 organisation. I prefer to explain all the details and problems that I faced, instead of a regular presentation of installation. I faced lots of problems during the transition and I want to share all these problems and their solutions in this article series. First of all, I will explain the existing Exchange 2003 infrastructure and then talk about the target Exchange 2007 infrastucture. I prefer not to use the redundancy technologies coming with Exchange 2007 to keep the transition simple. The old and the new organisations will be as simple as possible. During the planning and installation phases, Exchange Best Practise Analyzer (ExBPA) will be the biggest helping tool for us. We can see the problems in our existing Exchange infrastructure and also the problems of Active Directory with this little and handy tool. After solving the problems (if any), we will continue to build our new Exchange 2007 organisation step by step.
Lets have a look at the existing Exchange organisation first (Active Directory Domain Controllers and Global Catalogs are not shown in the figures below). In existing situation, there are three Exchange 2003 servers in LAN and one SMTP server in DMZ. One of the servers in LAN is used as a front-end server which is primarily for OWA access. The other two Exchange 2003 servers are holding the mailboxes. The SMTP server is running on Windows SMTP service. Antivirus and antispam products are used on SMTP server and mailbox servers, but i won’t give the names of the products :). Here is the topology:
Figure 1: Existing Exchange 2003 infrastructure
Actually the target organisation is very similar to the existing one. There will be four Exchange 2007 servers in LAN and one EDGE server in DMZ. Two of the LAN servers will be mailbox servers (MB), one of them will be Client Access server (CAS) and the last one will be Hub Transport server (HUB). CAS server will be a replacement for front-end server. Namely, users are going to use this server while using OWA, Outlook Anywhere and ActiveSync technologies. Mailbox servers will only handle the mailbox databases. HUB server will be responsible for e-mail transportation. This means that, all the e-mail traffic (inner or outer) will run through this server. EDGE server will be replacement for SMTP server in DMZ. In this infrastructure, antivirus and antispam softwares are going to be installed on EDGE and HUB servers. My advice is, try to use two different products on two different servers (if you can). Therefore, there will be a possibility that a virus can be caught by one of the product if the other one fails. Topology will be like below:
Figure 2: Target Exchange 2007 infrastructure
At this point, I want to talk about the methods that we can use during Exchange 2003 to Exchange 2007 transformation. There are mainly two methods: Migration and Transition. In migration method, mailboxes in Exchange 2003 organisation are backed up, a new Exchange 2007 organisation is build and all the backed up mailboxes are restored to the new Exchange 2007 organisation. On the other hand, in transition method, Exchange 2003 and Exchange 2007 servers are running together for some time. After the transfer of all the roles and mailboxes to the new servers are finished, Exchange 2003 servers are uninstalled. We are going to use the second method, transition method in our case. During the transition period, the topology will be like this:
Figure 3: Exchange organisation during transition period
After this long entrance to the subject, lets talk about what I have to do first about our new organisation. First of all I have to do the CPU, RAM and storage planning. For this purpose, I assume 10000 users in my organisation and also I assume that these users have moderate usage on Exchange mailing system (there are articles about the user profiles in Microsoft web site). I have to arrange some resource for all the server systems that I will use in my organisation (according to the moderate user profiles) and here is the planned resources:
CPU RAM Storage Area
Exchange 2007 01 Mailbox 4 core 12GB (5000 users) 2TB
Exchange 2007 02 Mailbox 4 core 12GB (5000 users) 2TB
Exchange 2007 03 CAS 2 core 2GB (1GB x # of core) 35GB
Exchange 2007 04 HT 2 core 2GB (1GB x # of core) 35GB
There has to be 1 Global Catalog server and 1 Hub Transport server in each site where we have a mailbox server. We have only one site, therefore this is not an issue (we already have them in our site). Lets talk about the steps that we have to complete during the transition. It is an important subject and here are the steps:
a) Installation of Windows operating systems and making them the members of AD domain
b) Installation of prerequisites for Exchange 2007
c) Installation of Antivirus software
d) Preparation of Active Directory for Exchange 2007 organisation (schema ve domain preparation)
e) Legacy AD permission arrangement
f) Entering / controlling the DNS records
g) Installation of Exchange 2007 to the servers
h) Installation of mail antivirus/antispam products to Hub Transport server
i) Transfer of Mailboxes
j) Transfer of Public folders
k) Transfer of organisational roles
l) Uninstalling the Exchange 2003 servers
By the way, the installation of server roles must be in an order. I mean; (i.e.) CAS role must be the first role that we have to install in our new Exchange 2007 organisation. Besides, there are some requirements in Active Directory infrastructure we have to take care of before the installations. Here they are:
a) All of the DC’s in AD must be Windows 2003 SP1 or above
b) AD forest and domain modes must be 2003 native mode
c) AD has to be prepared for Exchange 2007 organisation (PrepareSchema, PrepareAD) and replication of AD has to be finished to all sites
d) Client Access role will be installed and Exchange 2003 Frontend server will be uninstalled
e) Mailbox / Hub transport role servers will be installed
f) Mailboxes will be transferred from 2003 servers to 2007 servers
That is enough for Day 1. In Day 2, we will deal with the Active Directory. In addition, we will install our first Exchange 2007 server, the CAS server. Bye for now.
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