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David_Rudich_79's avatar
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Apr 22, 2015

Office 365 Migration

We setup a hybrid environment between two Exchange 2013 CAS servers and Office 365 and we're trying to migrate mailboxes to O365.


The two Exchange 2013 CAS servers are behind a pair of F5 LTM appliances and we're experiencing extremely slow transfer rates to the cloud (roughly 20MB an hour). Our bandwidth shows that it is pegged out at over 15Mbps, so I'm not sure where all of the data is going.


The F5 virtual server statistics show that it has sent over 4TB of data outbound, but I'm not sure where that data went to because it certainly didn't go to the migrated mailboxes.


Has anyone successfully setup Exchange 2013 server with F5 for the intention of moving mailboxes to O365? Did anyone experience any issues like this?


6 Replies

  • mikeshimkus_111's avatar
    Historic F5 Account

    Hi David, I've done some very basic testing here and saw about 100-200 MB/hour transfer rates. I know that O365 will automatically throttle back the transfer depending on network conditions, and that a mailbox with many small messages will take longer than one with fewer large ones, due to the pre-transfer indexing.


    Is it possible to point the migration directly at one of the CAS, to take LTM out of the picture?


  • Thanks, Mike. I think that may be the next step - to take the LTM out of the picture to see if we have any issues sending data directly to one of the CAS servers.


    The migration batch shows that it has transferred gigs and gigs of data, however we open one of the user reports to get additional detail it shows that zero messages have been transferred.


    I understand that the rates get throttled by Microsoft, however I think we should see better than 20MB / hour.


    • Dan_L1's avatar
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      Out of curiosity, did you ever go directly to the CAS server and see a change? We're experiencing a similar issue.
    • David_Rudich_79's avatar
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      I believe so and I don't think we saw any change. We determined that we could only do so many migrations at once before it causing all of the migrations at that time to halt. Once that happened, we had to cancel all migrations and start again - which eventually found that we couldn't do more than like 5 or 6 at a time to be reliable.
    • Aviv's avatar
      Icon for Cirrus rankCirrus

      Hi ! i had similar issue. microsoft had removed ddos protection to my tenant while migration and the speed was much better.