Shulou(Shulou.com)06/03 Report--

Recently, when migrating Office 365, we encountered a problem of high traffic and insufficient bandwidth. The environment is as follows:

Office365 E5 subscribes to the international edition. The client uses Outlook2013 to connect O365 mailboxes with 600 users and 50m Office365 dedicated bandwidth. When all user mailboxes migrate to Office 365, users complain about the slow sending and receiving of emails, check line traffic and find that 50m private network bandwidth is basically fully loaded during working hours, with an average use of 30m, a maximum of 70m, and a total traffic of 1.7TB in a working week (5 days)!

After packet capture analysis, it is found that the traffic is normal to the O365 server.

After careful analysis, select the top five users in the traffic list, go to the user's computer to check the Outlook configuration, and find that none of the five users have enabled cache mode, as shown below:

Modify the Outlook configuration, enable the cache mode, and reopen the Outlook. Later observation found that the modified 5 users did not enter the traffic TOP10! (Outlook2013 defaults to enabling caching mode! )

It seems that the problem lies in the difference between caching and online mode!

Ask the administrator to know that the previous Exchange server is local, and the user response cache mode is slower to send and receive mail than the online mode, so uncheck all the default cache modes in the user Outlook configuration and work in online mode!

For instructions between caching mode and online mode, you can refer to the official documentation:

Choose between cached Exchange mode and online mode of Outlook 2013

Https://technet.microsoft.com/zh-cn/library/jj683103.aspx

Configure cached Exchange mode in Outlook 2013

Https://technet.microsoft.com/zh-cn/library/cc179175.aspx

To change 600 users back to cache mode, use Group Policy configuration:

Enter the group policy management, add a new policy, go to: User Configruation\ Administrative Templates\ Microsoft Outlook2013\ Account Settings\ Exchange\ Cached Exchange Mode, and modify the Use Cached Exchange Mode for new and existing outlook profiles to: Enable

Apply the group policy to the corresponding OU of the AD to ensure that the configuration takes effect!

After a week or two of observation, the flow is compared and analyzed:

The following figure is the flow chart of a week when most users do not enable Cache mode, you can see that the average use of 30m, a maximum of 70m, a work week (5 days) total traffic reached 1.7TB!

The following figure shows the flow chart of a week after all users enable Cache mode, with an average use of 9m, a maximum of 48m, and a total traffic of 408G in a working week (5 days)!

The following figure is the result of continued observation in the next two weeks, and the traffic diagram is basically the same as the first week after revision, so it shows that the problem has been solved!

Summary: in the Office365 environment, because mailbox access needs to be connected to the outside through Internet, the bandwidth and latency are certainly not as good as those of the mail server locally (100m)

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