Staged Office 365 migration (exchange)

Hi, i need to migrate the mailboxes from a SBS2008 server to exchange online (office 365).
It is a  domain.local and i do not use Dirsync,ADFS.
I know how to make the  required DNS records on the Office 365 portal.
What changes are required on the DNS server (SBS2k8) so that outlook uses the Office 365 infrastructure? An SRV record  with the settings Domain: domain.local,Service:_autodiscover,protocol: _tcp,host offering this or a cname record or just nothing ?
I have also some mailbox users using the same SBS server with their  member clients in the domain.local but they use another smtp domain name and will not be migrated for the moment.Can they still work without any issue? Thank you
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colin_PaulConnect With a Mentor Commented:
Please refer to the following article: to To migrate mailboxes to Exchange Online. Try a  Staged Exchange Migration or Cutover Exchange Migration . The E-mail Migration Tool will detect all the mailboxes and create them on Exchange Online automatically.

Aame discussion is going there

Kind Regards
Colin Paul
Alan HardistyConnect With a Mentor Co-OwnerCommented:
The problem you are going to have is Autodiscover locally if you are keeping some mailboxes on a separate domain locally.

If you delete the Autodiscover virtual directory on the SBS server then clients will look to DNS to resolve Autodiscover and resolve to Office 365.  but if you are keeping some mailboxes locally, you need the local Autodiscover virtual directory so you will need to remove the mailboxes from the SBS server once the migration batch has completed.

Are you planning down-time to stop users from accessing their mail while the migration takes place?  If you aren't then I highly recommend that you do, having just completed a 100+ mailbox migration (Cutover) after finding several undocumented pitfalls that were nicely placed along the route (blog coming shortly).

How many mailboxes are you migrating and and how much data is to be migrated?

Vasil Michev (MVP)Connect With a Mentor Commented:
First of all, add additional UPN suffixes matching your SMTP domain and change the UPNs of all users you want to migrate. If you fail to do this, the mailboxes will be provisioned in the form and you will have to adjust it later.

As for Autodiscover, you only need the CNAME record. However, after you migrate the users to Office 365, disable the local mailboxes. Otherwise on a domain joined machine Outlook will always connect to the local mailbox. Read more about this in the following article (you can also adjust the registry settings to work around this as explained in the article):

Lastly, if you want to do a staged migration, you need DirSync. You can read about the process in the articles colin_Paul gave above.
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antwerp2007Author Commented:
Thank you all for the advice,i'll read the information :it is a small migration:22 mailboxes on monday for the users with the main domain name and soon 15 mailboxes with the other smtp domain name.
I let you know how the migration is going...
antwerp2007Author Commented:
The migration was not what i expected.I migrated during the weekend the mailboxes with migrationwiz and noticed (too late) that there were mails missing (many subfolders).
I changed the required DNS records regarding mail,added a DNs record cname autodiscover to the local DNS zones (SBS-server) and on monday the first 2 new outlook profiles were created succesfully.All the other profiles prompt for the credentials and autodiscover seems not to be working (anymore)? I searched every mailserver resource with the remote connectivity analyzer and used this information on the profile.
Vasil Michev (MVP)Commented:
Most likely Outlook is connecting to the local server first. Disable the mailboxes locally and use the registry fix in the article I gave above. If that doesnt help, run the "Test e-mail auto config" wizard locally and put the results there.
Alan HardistyCo-OwnerCommented:
I migrated 200Gb of data and it took about a week to migrate properly.  It does an initial sync and then once that is complete, it does a daily update sync.

How much data were you looking to migrate?

Outlook prompting for Credentials suggests that the client does not meet the criteria to run Office 365 in as much as it is missing updates.

Sign in to as the user, run the setup program and then let it tell you if the client meets the criteria needed or needs updates.  Let it finish and once it is, then you will be able to create an Outlook profile happily (assuming you zapped the Autodiscover Virtual Directory from your own server as I suggested in my initial post).

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