Active Directory Disaster Recovery

Domain Controllers  No PDC, BDC  All DCs are equal Some are more equal than others (operations masters)  Can demote DC to member server Can change its name this way  Can promote member server to DC

Active Directory Files  Default location %systemroot%\NTDS Ntds.dit — Active Directory database Edb*.log — Transaction log files Edb.chk — Checkpoint file to check data not yet written to database Res*.log — Reserved transaction log files (10MB each to reserve space in case disk fills up)

Garbage Collection  Runs periodically  Deletes tombstoned objects  Defragments database

System State  Includes everything that AD depends on, not just database files Database and log files SYSVOL shared folder Registry System startup files Class registration database Certificate Services database

Backing up Active Directory  Accessories/System Tools/Backup Allows backup of system state  TSM (to HFS) Backs up system object  Includes Active Directory  Third party  For complete backup, AD on all domain controllers must be backed up

Non-Authoritative Restore  Restores Active Directory to state before backup was made  Updates from other DCs are made via replication as usual

Authoritative Restore  Possible to mark part of Active Directory as authoritative on server where you are restoring it  Authoritative parts replicated to other DCs E.g. to restore deleted objects  Only part of database can be restored authoritatively  Can select subset to be restored authoritatively E.g. to restore deleted OU

References  How to remove orphaned domains from Active Directory 30/3/06.ASP 30/3/06.ASP  Domain controller server object not removed after demotion 16/3/64.ASP 16/3/64.ASP  How to perform an authoritative restore to a domain controller 41/5/94.ASP 41/5/94.ASP

References  Backup of the active directory has 60- day useful life cles/Q216/9/93.ASP cles/Q216/9/93.ASP  Removing active directory data after an unsuccessful demotion cles/Q216/4/98.ASP cles/Q216/4/98.ASP