Migration of legacy archives like Enterprise Vault are often left as the last part of the journey from on-premises servers to Office 365. A wide range of third-party migration tools are available, but many complex twists and turns await the unwary as they cope with journal reports, archive mailboxes, splitting and explosions, and the sheer amount of data to be migrated. It’s an interesting problem to solve.
The Office 365 Import Service does a good job of “bringing data home” by ingesting PST files and other data into Exchange Online mailboxes and SharePoint Online libraries. But sometimes you just want to do your own thing – and you can with the New-MailboxImportRequest cmdlet.