Unpicking Exchange upgrade

Scenario

An Exchange 2003 environment some years ago was started to be upgraded to 2010 using the legacy coexistance.

That upgrade did not go according to plan and due to various reason the project was suspended. This left a semi deployed 2003/2010 mix of servers with partially configured DAG/CAS.

The project has just been picked back up, however the requirement has changed. Rather than going to 2010 the decision has been made to go straight to 2016.

As this is a 2 hop process we need to remove the 2010 from the servers that will end up hosting the exchange environment. We will reinstall 2010 on some interim servers, migrate from 03 to 10, decommission 03 and migrate to 16.

Question (tl:dr)

Does anyone know/have a link how to undo an exchange 2010 install from exchange 2003 coexistence so that we can safely trash the server so that it will eventually be built with 2016?

I think you need to use some of that project money and get a proper expert in. I hesitate to say it, but maybe someone from MS themselves..

Trying to unpick something that was left half done 'some years' ago, and with the person who did it likely gone is way above a level of risk I'd be comfortable with.

that, unfortunately, is not an option.

Can you do a P2V and have a practice run in a sandbox environment?

I think Little_Crow is right - get someone in...

there is categorically zero funds for any consultancy/3rd party work.

Where are the mailboxes held? if there still on the 03 box it may not be all that difficult to roll back. If there on the 2010 id lean on the idea of finishing the migration and getting the house in order before moving forward.

But this really is a case of getting in experience. Good luck finding someone who still retains good knowledge of 03 mind

I'd start by documenting which server does which role.

If I was being 'forced' to do it in house then nutcase_1uk has the right idea.

Get the boxes virtualised into a lab and test the process to within an inch of it's life, and then test it the final inch too. Doing it live is never the same as test, but you'll have to satisfy yourself that you've prepared yourself as well as you possibly can.


A rough quote from 'Going Postal' by Terry Pratchett is appropriate: The job can be done Cheaply, Quickly, and Well - but you only get to pick 2.

If they want this job done cheaply but properly, then it's going to take time...

neil_g said:

there is categorically zero funds for any consultancy/3rd party work.

Click to expand...

How much email downtime is acceptable? I will go out on a limb and suggest the answers to these two questions aren't compatible with each other.

Finish the previous attempt first. That attempt will have updated your AD schema... which is irreversible. You will not be able to unpick it without an absolute amount of serious, agonising pain.

If you want to see the quickest way to **** an entire company off... do a botched exchange upgrade. I'd go as far to say you should demand they spend money to get experts in if you don't have the skills in-house.

If you have to do it yourself, there are hundreds of guides on setting up coexistence and properly migrating all mailboxes. Use those to work your way through the existing setup and identify what parts were originally missed, or just done incorrectly. It's probably not as broken as you think.

The guys in here are absolutely right if you do this in house then you really do need to virtualise and test it in a sandboxed environment before you end up in a whole world of pain. Esxi makes testing software upgrades like this a whole lot less risky.

Exchange upgrades can be an absolute nightmare when they start to go wrong. Do they have any email continuity in place that you can queue mail up in?

I mirror what others have said about getting in somebody who knows what they are doing if you aren't running something like esxi already.

As Hellsmk2 has already mentioned, it is imperative that you finish the migration to 2010 first, then remove all remnants of the 2003, with the schema updates that will have taken place to allow co-existence, if you try and back out you will almost 99% kill your mail server.

In addition to this, don't forget that only outlook 2010 + is supported by Exchange 2016, so updates to the outlook clients on your network may also need to be factored in

I'd seriously consider Hosted Exchange in your situation tbh, especially if you are currently on Exchange 2003!

Failing that I would not screw around with everything all at once. Why not finish the 2010 upgrade as per the previous plan, and then later do a 2010 to 2016 move when 2003 is gone?

As said above you wont be able to clear our the AD schema upgrades without causing yourself a world of pain.

You could create a resource domain and install 2016 there however im guessing you dont have the skills or possible knowledge to do this.

Best option is to create some P2V copies of your DC and exchange server, perform the upgrade to 2010, then up-to 2016.

Mailbox migrations will be online for 2010 SP3 to 2016 so aslong as you have the 2010 environment running there will be little downtime for your users (careful planning with outlook anywhere etc).

Exchange 2010 does have some disaster recovery switches but hard to say if they will be needed in your environment, i'd suggest running the exchange 2010 sp3 install and see what happens (on your test environment).

Please ensure you have backups of your DC and exchange server and they actually work, i've seen this all too often.

Your alternative is office365 or hosted exchange - this is usually a good op-ex model which most businesses like.