Summary of Failure Modes in Active Directory(FSMO)

Summary of Failure Modes in Active Directory(FSMO)

Failure ModeDescriptionUser Impact
Hardware/ software failure of single DC/GCSingle DC has failed due to hardware or software problems.  Network connections are upZero to very slight.  Users and Clients authenticate to the next available DC.  Users will locate the next available GC the same way.
Loss of complete siteSite is completely unusable due to disaster or network failure.  Everything in the site is inoperable or unavailableSlight impact. Users will be will authenticated to the next hop site or nearest DC
Data corruption in single serverDatabase is corrupted in a single DC.Zero to very slight, same as hardware failure.  Users and client machines authenticate to the next available DC in site or the nearest DC in the next hop site.
Data corruption throughout a single domainDatabase errors are spread throughout an entire domain.High.  Users may be unable to logon or unable to access basic functions until service is restored
Forest corruptionDatabase errors are spread throughout enterprise in all Domain Controllers. This could be as a result of a Schema or Domain Corruption.High.  Users may be unable to logon or unable to access basic functions until service is restored
Loss of network connection to site Site has lost all network connections.  Note: loss of only one of multiple network connections will be handled by the network support teamNone. User will be able to log on and perform all local functions, although they will not be able to access resources outside the site.
Loss of network connection to DC-less siteSite has lost all network connections.  Note: loss of only one of multiple network connections will be handled by the network support teamModerate.  Users will be able to log on to their own machines using cached credentials.  This will provide access to the local machine but will not allow access to any network resources.
Loss of Operations Master: Schema MasterThe server holding this role has failed, or the site holding this server has been lostZero.  This role is not used in normal operations.  Schema changes may not be made while this role is offline.
Loss of Operations Master: Domain Naming MasterThe server holding this role has failed, or the site holding this server has been lostZero.  This role is not used in normal operations.  Domains may not be created or deleted while this role is offline.
Loss of Operations Master: Infrastructure MasterThe server holding this role has failed, or the site holding this server has been lostZero.  This role is not used in the standard design because all servers contain the Global Catalog.
Loss of Operations Master:

RID Master

The server holding this role has failed, or the site holding this server has been lostZero to very slight.  Some DCs may be unable to create new user IDs or other objects while this role is offline.
Loss of Operations Master:

PDC Emulator

The server holding this role has failed, or the site holding this server has been lostZero to moderate.  Clients may experience password change (reset, unlock) problems due to replication latency while this role is offline.  This also means the loss of the reliable time source for the domain; however, this is unlikely to have any effect unless the outage extends for a very long time.

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