Moving to the cloud from an on premise solution should first consider the impact on bandwidth, especially if you currently have a data cap. Products such as Migration Wiz allow you to stage your data migration over a number of weeks as posted in one of my previous articles.
Great topic for anyone looking to do Mailbox Migrations into Office 365:
| Migration Tool | Migration method | User throttling | Migration-service throttling | Office 365 resource health-based throttling | Observed average throughput per hour and per client (if applicable) |
| Native O365/Simple Migration | IMAP4 migration | No | Yes | Yes | 5-10 gigabyte (GB) (50 concurrency) |
| Native O365/Simple Migration | Cutover Exchange migration | No | Yes | Yes | 5-10 GB (50 concurrency) |
| Native O365/Simple Migration | Staged Exchange migration | No | Yes | Yes | 5-10 GB (50 concurrency) |
| Native O365 | Hybrid migration | No | Yes | Yes | 10-15 GB (per On-premise Exchange 2010 CAS) |
| Third Party | MAPI | Yes | No | Yes | 0.5-1 GB |
| Third Party | EWS | No | Yes | Yes | 5-10 GB |
| Client Uploading | Outlook | Yes | No | Yes | 0.5 GB |
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