Office 365 incremental migration

How Does Incremental Migration Work?

EdbMails performs the initial data transfer from the source to the target and stores migration metadata locally in encrypted form for later incremental comparison. During a repeat run, EdbMails compares the current source data with the prior migration metadata to identify new or changed items that require migration. Previously processed items are normally skipped during this comparison, which helps avoid re-migrating the same data and can reduce repeated data transfer. Administrators should review migration results and validate the target before final completion.

Full Migration vs. Incremental Migration

Advantages of Incremental Migration

• Reduce repeated migration of previously processed items:

  Incremental comparison uses prior migration metadata to identify new or changed items for a repeat pass. In the normal workflow, this helps avoid re-migrating items that were already processed.

• Support staged migration and final cutover:

  When source mailboxes continue receiving or changing data during a migration project, repeat incremental passes can reduce the amount of data remaining for later passes. Administrators should validate migration results before final completion or cutover.

• Reduce data processed on later passes:

  Because later incremental passes focus on new or changed items identified by the comparison, they typically process less data than the initial full migration.

• Reduce repeated data transfer:

  By focusing later passes on new or changed items instead of reprocessing the entire dataset, incremental migration can reduce repeated data transfer. Microsoft 365 service limits and throttling still apply.

Incremental passes are useful for pre-staging, phased migrations, and projects that span multiple migration windows. Administrators who need to control which mailbox data is included can use Office 365 migration filter settings. After each pass, Office 365 migration reports can be reviewed to monitor migration results and investigate migration status or errors before final validation.

Other Available Migration Options

• Migrate by individually comparing each items in the target server

  The default incremental migration is generally sufficient for migrating missing items and those yet to be migrated. However, ‘Migrate by individually comparing each item in the target server’ option compels EdbMails to compare each and every item that has already been migrated. It is important to note that enabling this option may result in a slow down of the migration operation as it involves comparing each item individually.

  

• Migrate without an incremental check

  This option is useful if you want to re-migrate already migrated mailboxes or folders, maybe after deleting their contents from the target server. Note that while incremental comparison with your previous migration will be skipped, the re-migration process will still be performed incrementally to avoid duplicate items.

  

• Remove deleted source items from the target servers

  This option is useful if you have deleted source items after the initial migration and want to remove those deleted source items from the target server in the subsequent migration.

  

• Migrate Permissions (Folders like Inbox, Calendar, Contacts, etc.)

  Folder-level permissions often define who can access what within a mailbox, and this setting makes sure that structure isn't lost during migration. EdbMails lets you choose which permission types to carry over to the target: Default User, Anonymous User, and Other Users, giving you control over exactly how much of the source's access setup gets replicated.

  

• Migrate Rules (Inbox Rules)

  Inbox rules, like mail forwarding, blocking, etc, are easy to overlook during a migration but matter a lot to daily workflows. This setting carries those rules over from the source mailbox to its corresponding mailbox in the target, so users don't have to recreate their existing rule sets manually after the migration.

  

• Recursive Folder Scan

  Mailbox folders frequently contain sub-folders, which may themselves contain further sub-folders, forming a multi-level hierarchy. When Recursive Folder Scan is enabled, EdbMails scans and migrates items across every level of this hierarchy, ensuring that content within nested sub-folders is included alongside the top-level folders. This setting should be enabled whenever the source mailbox contains a multi-level folder structure that needs to be fully replicated in the target.

  

Frequently Asked Questions

1. What happens if I need to run the next migration from a different computer?

   The metadata EdbMails uses for comparison needs to be copied over to the new machine first. Once that's in place and the temp metadata location is set correctly, the migration continues the comparison accurately from the new computer.

2. Will running the migration again create duplicate items on the target?

   In the normal incremental workflow, EdbMails uses prior migration metadata to identify items that require migration and normally skips previously processed items. This helps avoid re-migrating the same data on repeat passes.