Forum Discussion

Copper Contributor

Mar 27, 2020

Help needed with a messy Office 365 migration and company split

I need help with a messy Office 365 migration and company split! We are two separate companies that share a network and server infrastructure and are parting ways in the next few months and I am ...

MVP

Mar 28, 2020

You could, yet you still need to set up e-mail transport between on-prem and Tenant 2 as long as there's a tenant 2 mailbox on-prem. Another limitation is that Company 2 won't have 'Exchange Hybrid', more of a rich-coexistence setup as AD Connect won't be able to perform things like writeback for Company 2. Define a migration endpoint for Company 2, set up staging of mailboxes for Company 2, then pick a cutover moment for them where you perform things like switch DNS record and finalize mailbox moves after which you can convert users in Tenant 2 to cloud only, and decommission ADConnect 2. That said, the preferred path depends a bit on the population and timeframes, for example if you can't perform a cutover due to numbers or organizing support.

tobif

Copper Contributor

Mar 30, 2020

Hi mderooij, thanks for the reply. Company 2 are happy to be in Tenant 2 with no AD Sync as they are unsure of their building situation for the next year or so. There are only around 30 users in each company so numbers are not a massive issue it's mainly the logistics of performing a cutover migration for one company while in the middle of, and retaining, a hybrid migration for the other company.

I guess what I'm trying to work out now is: given that I am already half way through a hybrid migration with Company 1 (a hybrid migration which won't be completed now for the next few weeks at least) is it ok to manually do a cutover migration for Company 2 (by manually adding in the necessary info such as the mail.onmicrosoft.com SMTP addresses) while keeping the configuration for the Company 1 hybrid and then at the end simply point the DNS for Company 2 to their O365 tenant and then remove their users from the Exchange server? And would I also need to remove the Azure AD sync for them first or do I do that at the end without it causing issues for the users in the tenant?

Thanks!