When you choose to force the replication, the wizard ensures that all linked attributes, such as group memberships, of the undeleted objects are correctly restored on all domain controllers.
This choice may result in considerable replication traffic, depending on the number of domain controllers in your domain. However, it is required because of the way links and deletions are dealt with in Active Directory. Before the restoration of linked attributes, the undeleted objects must be replicated to all domain controllers for the restored linked attributes to be correctly represented on each domain controller.
This requirement stems not from the wizard’s implementation, but from the way in which the data is replicated in Active Directory.
When you choose not to force the replication, you may risk a loss of linked attributes, such as group memberships, on replication partners after the normal Active Directory replication transfers the undeletion to all domain controllers.
For example, when you select a user to be undeleted, with the user being a member of a certain group, and choose not to have the wizard force the replication, the results of the restore on the representation of the user’s group memberships may vary. These variations are based on which objects replicate first after the wizard completes the restore.
If the undeletion of the user replicates first, then the group membership information of both the group (the members it contains) and the user (the groups he or she belongs to) will be represented correctly.
If the restore of the group replicates first, the replication partners will drop the addition of the (locally) deleted user from the group membership. The only exception to this is the user’s primary group, which is always represented correctly from both the user and group reference.
The wizard marks the undeleted objects so that they are replicated in a proper sequence. However, making changes to them before the replication is completed may break the proper sequence. Skip the replication enforcement if you are sure that no changes will be made to the restored objects until those objects are replicated to all domain controllers within the domain. Optionally, you may have the wizard force the incremental replication on the final step. You might also force the replication with a different tool, or wait for replication to occur on normal schedule.
In addition, you might skip the replication enforcement if you undelete objects whose deletions are not yet replicated within your domain. In that scenario, the objects in question are not marked as deleted on other domain controllers, which ensures the correct representation of linked attributes.
When you choose to stop the online restore operation, the wizard neither forces the replication nor restores linked attributes.
This choice implies that you wait until the undeleted objects are replicated to all domain controllers, and then restore those objects once more using the wizard. In that scenario, the second path of the wizard is used to restore the linked attributes on the undeleted objects. Stop the operation if the enforcement of replication in your domain is inadmissible for some reasons, but you want to be sure that linked attributes be represented correctly on all domain controllers.
Note that some AD DS and AD LDS (ADAM) object attributes cannot be restored by using Recovery Manager for Active Directory. For more information on these attributes, see Quest Knowledge Base Article 59039 “AD DS and AD LDS Object Attributes That Recovery Manager for Active Directory Cannot Restore” at support.quest.com.
The following table contains performance test results of agentless and agent-based restore operations on the machine running Windows Exchange Server 2008 R2. The agent-based restore is performed by a single Restore Agent instance.
Configuration of the test lab:
|Windows Server 2008 R2||2 x Intel Xeon E5-2651 v2 1,8 GHz||7,5|
Performance test results:
|Recovery method||Number of objects||Required time|
|Agent-based restore||1000||20 - 40 sec|
|10000||4 - 6 min|
|50000||23 - 34 min|
|Agentless restore||1000||40 - 70 sec|
|10000||6 - 10 min|
|50000||30 - 50 min|