What is Staged migration?
Staged Migration is a migration technique which migrates all the existing users’ mailboxes from on-premises Exchange to Exchange online (Office 365).In staged migration, the mailbox migration can be performed in two stages if necessary. This migration method is recommended for medium and large sized organizations with high data volumes. Because of the increased data volume, it cannot be migrated overnight or over weekends like cutover migration. For organizations that operate 24/7 and can’t afford longer downtime in their operations, staged migration is an ideal solution. Basically, the staged migration process is divided into two stages.
In the first stage, you migrate data which is either older or newer than a particular date. You then transfer the domain to the destination server and update the MX records after you complete the migration. In the second stage, you migrate the remaining data from the first stage.
An advantage of the staged migration method is that you migrate the most recent data first during off-hours or on weekends, then transfer the domain and update the MX records. This methodology enables your users to resume working in the new environment while you migrate the remaining data from the source to the target.