Performance: G Suite to Office 365 mail migration

There are several considerations regarding email migration performance. The Cloudiway migration platform uses all available resources to provide the fastest migration possible and can support both small and large migrations. The on-demand migration engine allocates the capacity that you need to migrate the volume of data of your choice in the time slot you have allocated. However, there are limitations.

Many mail systems can heavily throttle users. When you perform too many calls, the remote server will begin throttling and decrease the number of calls that can be performed each minute, thus reducing the migration throughput. Cloudiway constantly attempts to work at the maximum capacity allowed to achieve excellent throughput.

Google mail migration limitations:

Google limits migration to 2.5 GB per user per day. Usually, some additional data migration is possible before throttling begins. When throttling does begin, the Cloudiway platform will attempt to migrate 10 GB of data per user, then sleep for 6 hours and automatically restart the migration where it left off.

Office 365 mail migration limitations:

Office 365 uses throttling policies to limit the resources consumed by a single account. To maximize throughput and limit throttling, Cloudiway follows Microsoft best practice and uses impersonation. An account that has impersonation privileges can impersonate 100 users concurrently to migrate 100 mailboxes in parallel. The platform uses EWS (Exchange Web services) protocol; Microsoft theoretically allows throughput of around 300 MB per user per hour.

The Cloudiway platform typically sees throughput between 200 Mb and 300 MB per mailbox per hour. This gives an average throughput of around 500 GB per day with a constant migration of 100 concurrent mailboxes. If you wish to further improve throughput, you can create distinct migration accounts and create additional connectors in the platform.

For example, if you create two targets Office 365 connectors (each with its own distinct migration account), you can migrate 200 mailboxes concurrently and reach a throughput of around 1 TB per day. Mailbox item count is also a factor: because Office 365 throttling policies limit migration to 1500 to 1800 emails per user per hour. Therefore, a mailbox with 1,000,000 small emails will be slower to migrate than a mailbox with 1,000 large emails containing attachments.