Down time for migrating to office 365

[capr]

hello, I am looking to move our email over to office 365 from godaddy. We currently use IMAP and SMTP to do email and I need to move each user to the new service and migrate their email as well. I have 6 users...

What's the expected downtime? I also need to make sure we get our domain name on there and not have this blha.onmicrosoft.com stuff...

This is my first time doing this so I will add 30 minutes to account for me screwing things up.

[+LogicalApex MVC]

The transition time will depend on the TTL for your DNS A records and MX records and if the calling machine has connected to your server within that TTL.

Basically, it can take anywhere from 1 minute to 48 hours or longer depending on what you configured on the DNS side of things. Keep in mind that since this is calling machine dependent email will scatter in as caller's cache expires and the same will be true for users.

[+BudMan MVC]

^ correct, changing the record on your current domain MX record to point to the new email server for your domain (microsoft servers) will depend on the current TTL of your MX record.

So lets say its 24 hours. Now you don't know someone might of just cached that 1 minute before you changed it. So for the next 24 hours they are still going to send mail to your old server.

I would suggest as prelim to moving that you lower the TTL of your MX now to something short, say 5 or 10 minutes. Then when you do change it, you only have to wait 10 minutes before you know everyone on the planet will be pointing to your new MX record.

So for example for neowin.net I query one of their authoritative name servers to get the TTL they have set.

dig @ns1.neowin.net neowin.net MX

;; QUESTION SECTION:
;neowin.net.				    IN	  MX

;; ANSWER SECTION:
neowin.net.			 21600   IN	  MX	  10 aspmx4.googlemail.com.
neowin.net.			 21600   IN	  MX	  10 aspmx5.googlemail.com.
neowin.net.			 21600   IN	  MX	  1 aspmx.l.google.com.
neowin.net.			 21600   IN	  MX	  5 alt1.aspmx.l.google.com.
neowin.net.			 21600   IN	  MX	  5 alt2.aspmx.l.google.com.
neowin.net.			 21600   IN	  MX	  10 aspmx2.googlemail.com.
neowin.net.			 21600   IN	  MX	  10 aspmx3.googlemail.com.

They have ttl of 21600 seconds or 6 hours. So if neowin changed their MX record this very second, for the next 6 hours it is possible for people to still sending to these googlemail servers. Now in 6 hours 1 second, that cache will expire and their ISP dns will have to lookup the record again - so at that time they would get the new MX record for the domain.

Once the TTL of your old MX record has expired you can shutdown your old server. So the lower the TTL before the move the less time you have to keep your old server online for.

You could if you wanted also just lower your ttl, and then once you make the change just shutdown the old server right away. What should happen is when someone tries to send user in this domain an email and server does not answer it will fall back to try and send the email again later, say 15 minutes. If your TTL is short enough when it goes to try and send it again it should get the new MX record. Most email servers will try and resend email multiple times, increasing the wait time before resend each time to some limit before it kicks it back to the user saying it could not send the message. These retry and wait times will depend on what the admin of the sending server set. But normally your talking hours and hours before you get an actual kickback that could not send.

So if your TTL is short, you should not have any of those issues.

[Harrison H.]

Capr,

Were you only looking for down time information regarding DNS, or for the entire migration? If you are talking about the entire migration, with the small amount of users you have, it should take about an hour to three hours depending on the amount of mail you have, and how quick you are, and how much planning you put into it. I've migrated my company twice now, so I'm used to doing it in a quick manner. If you'd like a run down on a good migration plan, let us know.

[sc302 Veteran]

Just migrated to office365, dns took about 15 minutes. You will see that when you put in your file record in dns as what is laid out by the migration process as proof of ownership over the domain.

[capr]

Thanks a lot everyone, I set everything up and microsoft recommended the 1hr TTL times in their walk through so I just stuck with it. I can see that emails are going to Godaddy right now so hopefully that will change in an hour.

I am starting the actual email saving and migrations now...

I don't need to delete the emails on godaddy do I? If I just don't renew the contract and left things alone, it should be fine right?