How many and which DCs is it recommended to backup? (4219351)

To restore deleted or corrupted objects with the Online Restore wizard, it is recommended:

• to back up at least two domain controllers for each domain for redundancy
• to back up at least one domain controller per AD site (assuming your AD sites reflect geographical deployment) to minimize network traffic after restores

If you intend to restore cross-domain group membership information, then it is also necessary to back up a global catalog server. The global catalog server backup must be created with the option When backing up Global Catalog servers, collect group membership information from all domains within the Active Directory forest enabled on the System State tab of the Computer Collection Properties dialog box.

For offline restores of DCs

If you intend to use Recovery Manager to recover from a full DC failure (using the Repair Wizard), it is recommended that you back up all domain controllers in all domains.

To be prepared in the case of a forest-wide failure, it is recommended that you backup all domain controllers in all domains with the option Collect Forest Recovery metadata enabled on the System State tab of the Computer Collection Properties dialog box. This option creates backups to be used by Recovery Manager Forest Edition for recovering a forest. The Forest Edition of Recovery Manager must be purchased and deployed before this option is available.

For more information, refer to the Recovery Manager for Active Directory Deployment Guide.