This article describes how delta migration works.
Delta migration during a Mail Migration
Cloudiway migration internally stores a reference (messageID or ItemID) to all items it migrates.
When you remigrate a mailbox (delta pass), items that have already been pushed are not migrated again.
The delta pass mechanism ensures that no duplicate content is created in the target in order to avoid duplications.
After the first migration pass is compete, you have up to 90 days to perform delta passes and final cutover for that mailbox.
If a target mailbox is emptied, already migrated items are not pushed again because the list of migrated items is maintained in the Cloudiway cache.
Therefore, if you need to remigrate an entire mailbox, you would need to use a new Cloudiway license, delete the user from the Cloudiway user list and recreate it. This will be considered a new user and this will also consume a new Cloudiway license.
If you have moved the domain from the source to the target and need to perform one more delta pass, you will need to use the Switch Domain Global Action.
When migrating from Exchange or Microsoft 365, changes after migration are propagated (it could be a mail deletion, a move of a mail from one folder to another, a mail passed as read, etc…). Deletions from Google are propagated.
When migrating from other sources, these changes are not propagated (the respective APIs do not propose a way to detect the changes between two passes).
The calendar migration engine works as a synchronization engine. Depending on the scenario, updates and deletions of appointments can be propagated during delta passes.
Google as the source and other sources: changes are not propagated ( There are no APIs to detect changes between two passes).
Detecting changes would require to entirely read the source and the target and analyzing the changes.
Exchange or Office 365 as source: changes are propagated.
See more about calendar migration in this article.
During a delta pass, new contacts are migrated. Deletions and modifications are not propagated.
During a delta pass, new tasks are migrated. Deletions and modifications are not propagated.
Migration to an existing mailbox
Cloudiway adds items to an existing mailbox.
It does not touch, modify or delete items that have not been pushed by Cloudiway.
This means that:
- Existing items are not overwritten.
- If you entirely migrate 2 times a mailbox (with 2 Cloudiway licenses), it duplicates the items: The second migration is considered as a new migration to an existing mailbox with items.