Email migration to Office365. Two mx records.

[dandy34]

Getting ready to migrate from Groupwise 8 to Office365. As we'll be moving over 100GB of data offline, we have to migrate a few users at a time.
As this means we have to maintain two domains with the same name, I'm hoping to add an MX record to the new domain while keeping the original intact but with lower priority.

Anybody have any thoughts on this?

 

[vpetersson]

Hi Dandy34,

I'd recommend doing the migration in one go. 100GB of data isn't a lot when it comes to email migrations. We do migrations much larger than this frequently. However, it of course comes down to bottlenecks. If your Groupwise server is on a slow connection, it could of course be a problem.

Since MX-records works by priority, adding a lower value MX-record will re-route all emails to the new server, unless it fails. In which case, the next server with higher priority will be used. Hence if you add an MX-record for Office365 with lower value than the Groupwise-server, the Groupwise server will only be used if Office365 fails.

While the whole notion of 'two domains' throws me off a bit, it sounds like what you are trying do describe is 'dual delivery,' in which case the incoming emails are being delivered to two different email systems simultaneously. This however, isn't handled on the MX-level, but rather by the primary email server (which will deliver emails to the second server).

I hope that helps clarify things a bit, but let me know if you have any questions.

Regards,
Viktor Petersson
YippieMove / WireLoad