Where and when to install Exchange Hybrid

[Tom Gould]

Well this is not as much as a looking for a resolution but what others are doing out there and opinions on a best course of action. 

I recently had a friendly conversation about hybrid migration while planning one myself. Currently i am looking at an envrionment running Exchange 2010 (2Mailbox servers, 2CAS/HUB servers). They are migrating to Office 365 and end vision is to only be left with an Exchange 2016 hybrid server for administration, management, you get the picture. 

I know that both would work but i am curious what others recommend. @Paul Cunningham do you have a recommended approach that you prefer? 

1. Would you cut mail flow over to EOP, hybrid with 2010, do the migrations, clean up on prem Exchange, and then install 2016 at the end?

Or

2. Would you install 2016, setup Exchange 2016, cut mail flow to EOP, perform the migrations through Exchange 2016 from the 2010 mailboxes, then just tear down 2010 at the end??

Or 

3. Some other way of doing it?

[#2 · Accepted solution]

Hi Tom,

Option 2 with a few changes to the process

. Install 2016, setup Exchange 2016, Setup Hybrid, cut mail flow to EOP (Test First), perform the migrations through Exchange 2016 from the 2010 mailboxes, then just tear down 2010 at the end

[#3]

I agree with this approach and is what I would prefer. But I was having a friendly conversation on what approach people take. Curious what Paul and others recommend. 

[#4]

You can do it both ways. Option 2, as Nuno already mentioned, would be the best and simplest one.

[#5]

This is a path we take with our clients for pro serve migrations, and we follow option 2, of putting the 2016 server in place, then doing the migration.

At the end of the migration you can decomm your old 2010 servers without a ton of extra hassle, and the 2016 server looks and feels like Office 365. It puts you in the end state as soon as your migration is done, and has some of the pre-work going on when users are unaware and still just doing their normal thing. By following this path too, there is typically some AD cleanup work that happens when you upgrade the exchange schema, which means a cleaner/better foundation as a starting point in O365.

These are the primary motivators for my company, which causes us to follow option 2.

The one "got ya" that we have come to look out for is Public Folders. The architecture of Public folders changes pretty drastically from 2010, to 2013/2016. When you perform the Exchange Schema upgrade to your AD, which you have too in order to do 2016, then your Public Folders in 2010 start having issue for anyone you have moved.

The way you get around this is by migrating the PF's to 2016 as cross platform move, then doing commands in Office 365 to have the 2016 folders be discoverable in Office 365. Then you stage and move them over just like a remote mailbox move. The first time we did this it was kind of a cluster, but we have sense got much better at the process.

Some good resources if you do have PFs:

Overview of what you can do- https://technet.microsoft.com/en-us/library/dn249373%28v=exchg.160%29.aspx?f=255&MSPPError=-21472173...

Migration Commands - https://technet.microsoft.com/en-us/library/dn874017(v=exchg.150).aspx

Great blog - https://blogs.technet.microsoft.com/undocumentedfeatures/2017/04/08/migrating-hybrid-public-folders-...

Hope this helps!

[#6]

There is also a 3th option.

Configure Exchange 2010 in Hybrid mode. Then migrate al the users and shared mailboxes to Office 365.

If you have Public folders let them exist in co-existing mode. When the complete migration is done and you public folders are working in Co-existing then upgrade the exchange server which has the hybrid configuration installed to exchange 2016 and you are good to go.

Future approaches are: Make the public folders on 2010 read only give users time to move their data over to a shared mailbox or office group. And when all the Public folders are empty decommission the Exchange 2010 servers.