After you have successfully added a migration pair, you need to specify objects which you plan to synchronize with or migrate to Microsoft Office 365. Migration Manager for Active Directory organizes the objects into collections. A collection is a set of objects that are migrated to Microsoft Office 365 at the same time by the same instance of Directory Migration Agent.

Considerations

When dividing migration scope into collections you should consider the way that linked attributes (such as group membership) get resolved:

• Linked attributes always get resolved in the scope of the collection. For example, if you migrate a group and its members within the same collection, the membership will get migrated.
• Linked attributes are also resolved for previously migrated objects. For example, if you first migrate users and then migrate a group, the group will be migrated with its membership.
• Backlinks (such as "member of") are not updated across collections. For example, if you first migrate a group and then in other collections migrate its members, the newly migrated accounts will not get added to the target group. If you have to migrate a group before its members, you can restore the membership by either re-migrating the group or doing full re-synchronization.

Choosing between Collection Types

Migration Manager for Active Directory has two types of collections described in the table below:

Collection Type	Used to	Populated
Static	Migrate a group of objects with non-default mapping or matching rules Re-migrate groups after their members were migrated to Microsoft Office 365 to resolve group membership Synchronize a group of objects to keep their attributes actual in Microsoft Office 365 Re-migrate users after their mailboxes have been created in Microsoft Office 365 for migration of the following mailbox attributes to Microsoft Office 365: The mailbox and the Send As permissions; The linked attributes such as group membership, the Send On Behalf permission, the publicDelegates attribute, and the others. NOTE: See the Mailbox Permissions Processing Considerations for more details on mailbox permission migration.	Directly with objects, by executing queries or by importing objects from .CSV files
Dynamic	Synchronize all objects from Active Directory domain with Microsoft Office 365 to maintain a unified global address list (GAL)	By specifying a particular container in Active Directory domain and a filter to apply to it Note that dynamic collections are updated automatically when content of the container is changed.

The two following sections will describe how to create and populate static collections and dynamic collections.

Note: Dynamic collections can be involved only in directory synchronization tasks and cannot be used for migration tasks. For more information on migration and synchronization differences, see this section.

Caution: Prior to creating any collections, review and configure if necessary matching and mapping rules on migration pair level. Those rules will affect all your collections created afterwards.

Adding a Static Collection

To add a static collection, select your migration pair in the management tree, open the Collections tab and click the New Collection item in the Actions pane and then specify the following:

1. A name for the static collection
2. The instance of Directory Migration Agent that should process this collection
3. Whether coexistence should be enabled for the collection immediately after collection is created.

Caution: Select to enable collection for coexistence only if you are sure that default matching and mapping rules for this collection satisfy your needs.

To populate the collection with objects use Add Objects, Query Objects and Import Objects action items from the Home tab according to the table below.

Action Item	Do What	Useful When
Add Objects	Adds objects and containers directly from Active Directory	You want to add objects that can be easily located in the Active Directory.
Query Objects	Filters objects from Active Directory by specific attribute values or add objects that match specified LDAP query	You want to select mailboxes based on some custom criteria: for example, mailboxes of all users that have a specific Active Directory attribute.
Import Object	Imports objects from CSV file. File should contain one column with attribute name in the first row and appropriate attribute values in the subsequent rows. For example: Name User1 User2 User3	You already have a list of objects with specific attributes which you want to add to a collection.

To verify that the static collection is populated correctly or to make any adjustments to the collection membership, go to the Objects tab and check the resulting list of objects.

To review and configure if necessary matching and mapping rules for the collection, go to the Matching or Mapping tabs, respectively.

Adding a Dynamic Collection

To add a dynamic collection, select your migration pair in the management tree, click the New Dynamic Collection item in the Actions pane and then specify the following:

1. A name for the dynamic collection
2. The instance of Directory Migration Agent that should process this collection
3. Whethercoexistence should be enabled for the collection immediately after collection is created
4. Container to search objects in and a filter to refine results.

TIP: Click Preview to display a resulting list of found objects that will be added to the dynamic collection.

To verify that the dynamic collection is populated correctly, go to the Objects tab and check the resulting list of objects.

If you need to change container which objects should be synchronized or edit applied filter, click the Change Scope action item on the Object tab and perform necessary adjustments.

To review and configure if necessary matching and mapping rules for the collection, go to the Matching or Mapping tabs, respectively.