Migrating from a server 2003/2008 domain to 2012

davetherave2

davetherave2

davetherave2

Soldato
Joined
27 Mar 2003
Posts
2,710
Hi guys, wondering if someone can assist with this in some way. More after qualification about a position upgrade route and if what I am potentially going to propose is sensible or if I am talking complete *expletive*

Although I am a developer by trade (these days) I have a lot of support knowledge and the current support team for our business is looking to do a wholesale upgrade off all older servers running 2003/2008 to 2012 and at the same time upgrade our Exchange 2003 farm to 2013.

I know a massive project to try and implement. (I say massive it is probably the best part of 40 servers and 6 exchange boxes (1 front end, 5 back end)

Now I understand that tech has move on a lot since this was implemented and am informed that exchange no longer needs the front end/back end setup and can just have a single server or several servers working in unison. The business is looking to transfer all the mailboxes and public folders (approx. 1000+) to one uber exchange 2013 box. Is this sensible or should it be split across multiple instances? The plan is to remove all our remote exchange boxes onto one site and these boxes have 400+ mailboxes sat on their servers.

In addition to this our AD, GPO, security and distribution groups are a horrendous mess. After years of what seem to be mismanagement by previous support staff there are a million and one AD accounts, security groups and gpo's that no one has a clue what is going on and then to top it off the security groups aren't really being used properly and individual user accounts have been granted specific access rights to various network folders across the corporate lan. So it is nightmare to manage and ensure the right people have the right access.

Now I have come up with two options (although I think option 1 is wrong from the get go) which are:

1) Create a clean 2012 domain that runs in parallel to the live domain and create a trust between the two domains and migrate groups of users at a time until everyone has been removed from the old domain and then transfer all domain services like dhcp, dns etc over to the new domain and then turn just switch the old one off. (I'm not sure how the new exchange infrastructure will work in this scenario)

2) Create new 2012 servers in the live domain and then create entirely new ou's gpo's, groups, file shares etc. for users and then migrate them over as and when we can. Test them out and then slowly migrate other services over to 2012 machines. Once all the old policies etc. have been emptied of live users etc. then we can just delete these from the system and we should be left with a nice clean domain and something that is more maintainable moving forward.


Now I guess number 2 is probably the way to go as it has less risk involved as we can just decommission older servers as and when we are ready to. I also think it would probably be easier to get the 2012 Exchange environment working in this scenario.

Now does what I am proposing from a conceptual point of view seem sensible or is there a third or maybe a fourth option to consider.

One thing I was potentially thrashing about is linking the new 2012 servers up to azure and then having this as potential failover for our remote sites (Would this then remove the need to have local AD servers on these sites?)

Again it has been a while since I used my support skills for any length of time so just wondering if this is considered the best solution.

Thanks in advance for any assistance.
 
Option 2, whilst looks to be more work, looks to be your best option. You seem to also have it spot on with the plan in that you build a new OU, GPO and Security Group structure and move people into it.
As part of the work you need to get your company to start informing IT when a user leaves the company. If you highlight this as a risk to security that people can still get their mail after leaving the company then maybe this will kick them into gear. I am sure there is no issues when it comes to taking people off payroll!
 
1000+ mailboxes on a single server -- can you imagine the stress and pressure and fallout there will be if anything goes wrong with that server?

Both Microsoft and HP have Exchange 2013 calculators; check them out. You will need to know a few things:

- Number of mailboxes
- Average mailbox size
- Average number of emails sent and received per day, per mailbox
- Average message size

Plenty of other variables, but those are the key ones. This will give you very precise size and IOPS requirements, and a recommendation for number of servers, number of spindles per server, even number of mailboxes per server.
 
Also, cross-forest mail migration is much much harder than intra-forest.
 
I am not sure if you can go from exchange 2003 to 2013. I don't think its possible. You either have to go from 2007 or 2010 to 2013.

For AD I would install a 2008/12 domain and then make the 2012 domain the primary domain on the network. Then leave it a few weeks, during this time move all services on the network to point to the new domain. Then decommission the old DC one by one, very cautiously.

Then to clean up AD, you can just create new OU and move the objects around. The main consideration with that task is group policy and any services that may sync with ad ou's.

To clean up ad i create new ou and block inheritance on the ou and then relink the relevant gpo to the new ou and transition everything across. Once you have the new clean areas, move all old objects to another area out of the active GPO and then if any problems you can move the objects to the correct place. After a few weeks in the non active area and you can confirm the objects are not used, delete them.

Adding 2008 dc to 2003, check second post:
http://forums.techarena.in/active-directory/1298956.htm

Decommission dc:
http://technet.microsoft.com/en-us/library/cc755937(v=ws.10).aspx

2003/2012 co existence not supported:
http://technet.microsoft.com/en-us/library/aa996719(v=exchg.150).aspx

As you would need to run both 2003 and 2013 servers for a few weeks at the same time while you move the mailboxes you will be forced to upgrade to exchange 2010 first. I just did two exchange 2010 upgrades and came across this same problem, but we purchased 2013 licenses and it allows for 2010 installation and will probably upgrade to 2013 in a few years.
 
Last edited:
Swarfega said:
How many of them 1000 are users that have left the company I wonder?
Click to expand...

There are about 250 people within the business. But due to the nature of our business we have mailboxes that are created for specific needs like contact mailboxes for a particular client etc.

There is probably a couple of hundred that can be removed but we would still be looking at around 400 - 600 active mailboxes at the moment.
 
Thanks for all the advice. I was kind of going down the second option and confirmed it with an old work mate that has recently been doing some of this type of work.

So I feel more confident in suggesting this as a possible upgrade route to try and unbundle any hidden nasty things sat in our ad. No doubt something will break as they tend do when embarking on such a big project but at least as long as we do it in baby steps we can resolve anything before it impacts the business.
 
You will need to go to Exchange 2010 first. There's no direct path to 2013 from 2003.

Also, when you move to 2013 make sure all user mailboxes have been migrated to 2013 before you move public folders over, as 2010 mailboxes wont be able to access a pf on 2013.

PF migrations between 2010 and 2013 are also needlessly painful. Be warned!
 
You must log in or register to reply here.
Back
Top Bottom