Hybrid O365 Deployment

New Contributor

We currently have a 120 user Exchange 2013 on-prem environment and would like to start O365 for 1 Department - is this possible?


I've been trying get the company to move to O365 and would like start with 1 department of 10 users.


Single Domain, 120 Users - around 40 have left so I guess 80 live users

I have done some Research and was think of using CodeTwo Software but open to suggestions.

Looks like I will need to setup Hybrid O365 deployment wit O365 E3


If I want to start with say 10 users migrate to O365 - how many licenses do I need?


Backup - any suggestions? I don't want to rely on Microsoft


BTW: Average mailbox size is 30Gb. We have a 100mbps Leased lined is there any way to work out how long it would take to Migrate say 20 mailboxes?

4 Replies

Hi @Chriss60


Yes, when you implement hybrid you choose what users migrate to Office 365, you could do it by waves.


You can do by departments.


You can migrate with native tool of Microsoft using Mailbox migration from Office 365 (Exchange Online Admin Center), you will need to setup hybrid first.


Office 365 has license per user if you need to migrate 10 users you will need 10 licenses. About backup, if you use Office 365 E3 at least you will have DLP that can retain your mail.


About time of migration it depends always based on your location, number of items, your server and so on, only after you migrate your first mailbox you will have a medium time of a mailbox migration.


Best Regards, 

Nuno Árias Silva

One more question...

I was told my another Admin that in order to deploy O365 in Hybrid setup E3 is required
but I've not seen any reference to this elsewhere.

I know E3 has DPL & enhanced Security but in terms of actual product Office, Sharepoint, Teams, Yammer etc. O365 Business Premium has everything..

So, is O365 Business Premium an option here?

Hi @Chriss60,


You can implement hybrid, you can also add a Trial on E3.


You can see the following links with more information about the differences.




A migration of a few thousand emails is typically complete in a few hours or less. Under ideal conditions we transfer anywhere from 250-750 MB per hour. A migration of tens of thousands of messages my take less than a day and a migration of hundreds of thousands of messages usually requires a day or two to complete.