Overview
FRS is a multi-threaded, multi-master replication engine that
Windows Server 2003 and Windows 2000 domain controllers use to replicate system policies and logon
scripts for Windows Server 2003, Windows 2000, and earlier-version clients. In Microsoft Windows NT,
the LanMan Replication (LMREP) service handled replication. FRS replaced LMREP
in Windows 2000. You can also use FRS to replicate content between Windows 2000
servers that host the same fault-tolerant Distributed File System (DFS) roots
or child node replicas.
When you deploy Windows-based domain
controllers or member servers that use FRS to replicate files in SYSVOL or DFS
shares, you may have to restore or reinitialize individual members of a replica
set if replication has stopped or is inconsistent. In some scenarios, you may
have to rebuild the whole replica set from scratch.
The
FRS BurFlags registry
key is used to perform authoritative or nonauthoritative restores on FRS
members of DFS or SYSVOL replica sets.
Note: System state backups of Windows member servers and domain
controllers do not include the FRS database that maintains a mapping of files
that are held in local FRS trees and a master list of FRS files.
For more information
about exclusions for Ntbackup.exe, click the following article number to view the article in the Microsoft Knowledge Base:
233427
Files and folders that are not backed up by using the Ntbackup.exe tool
back to the topRestoring FRS replicas
The global
BurFlags registry key contains
REG_DWORD values, and is located in the following location in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\NtFrs\Parameters\Backup/Restore\Process
at Startup
The most common values for the
BurFlags registry key
are:
- D2, also known as a nonauthoritative mode
restore
- D4, also known as an authoritative mode restore
You can also perform
BurFlags restores at the same time as
you restore data from backup or from any other known good source, and then
restart the service.
back to the topNonauthoritative restore
Nonauthoritative restores are the most common way to reinitialize
individual members of FRS replica sets that are having difficulty. These
difficulties may include:
- Assertions in the FRS service
- Corruption of the local jet database
- Journal wrap errors
- FRS replication failures
Attempt nonauthoritative restores only after you discover FRS
dependencies and you understand and resolve the root cause. For more
information about how to discover FRS dependencies, see the "Considerations
before configuring authoritative or nonauthoritative restores of FRS members"
section later in this article.
Members who are nonauthoritatively
restored must have inbound connections from operational upstream partners where
you are performing Active Directory and FRS replication. In a large replica set
that has at least one known good replica member, you can recover all the
remaining replica members by using a nonauthoritative mode restore if you
reinitialize the computers in direct replication partner order.
If you
determine that you must complete a nonauthoritative restore to return a member
back into service, save as much state from that member and from the direct
replication partner in the direction that replication is not working. This
permits you to review the problem later. You can obtain state information from
the FRS and System logs in the Event Viewer.
Note: You can configure the FRS logs to record detailed debugging
entries.
For more information
about how to configure FRS logging, click the following article number to view the article in the Microsoft Knowledge Base:
221111
Description of FRS entries in the registry
To perform a nonauthoritative restore, stop the FRS
service, configure the
BurFlags registry key, and then restart
the FRS service. To do so:
- Click Start, and then click
Run.
- In the Open box, type
cmd and then press ENTER.
- In the Command box, type net
stop ntfrs.
- Click Start, and then click
Run.
- In the Open box, type
regedit and then press ENTER.
- Locate the following subkey in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NtFrs\Parameters\Backup/Restore\Process
at Startup
- In the right pane, double-click
BurFlags.
- In the Edit DWORD Value dialog box, type
D2 and then click OK.
- Quit Registry Editor, and then switch to the
Command box.
- In the Command box, type net
start ntfrs.
- Quit the Command box.
When the FRS service restarts, the following actions
occur:
- The value for BurFlags registry key returns to 0.
- Files in the reinitialized FRS folders are moved to a
Pre-existing folder.
- The FRS database is rebuilt.
- The member performs an initial join of the replica set from
an upstream partner or from the computer that is specified in the
Replica Set Parent
registry key if a parent has been specified for SYSVOL replica sets.
- The reinitialized computer performs a full replication of
the affected replica sets when the relevant replication schedule
begins.
Note: The placement of files in the
Pre-existing folder on reinitialized members is a
safeguard in FRS designed to prevent accidental data loss. Any files destined
for the replica that exist only in the local
Pre-existing folder and did not replicate in after
the initial replication may then be copied to the appropriate folder. When
outbound replication has occurred, delete files in the
Pre-existing folder to free up additional drive
space.
back to the
topAuthoritative FRS restore
Use authoritative restores only as a final option, such as in the
case of directory collisions.
For example, you may require an
authoritative restore if you must recover an FRS replica set where replication
has completely stopped and requires a rebuild from scratch.
The
following list of requirements must be met when before you perform an
authoritative FRS restore:
- The FRS service must be disabled on all downstream partners
(direct and transitive) for the reinitialized replica sets before you restart
the FRS service when the authoritative restore has been configured to
occur.
- Events 13553 and 13516 have been logged in the FRS event
log. These events indicate that the membership to the replica set has been
established on the computer that is configured for the authoritative
restore.
- The computer that is configured for the authoritative
restore is configured to be authoritative for all the data that you want to
replicate to replica set members. This is not the case if you are performing a
join on an empty directory.
For more information, click the following article number to view the article in the Microsoft Knowledge Base:
266679
Pre-staging the File Replication
Service replicated files on SYSVOL and Distributed File System shares for
optimal synchronization
- All other partners in the replica set must be reinitialized
with a nonauthoritative restore.
To complete an authoritative restore, stop the FRS service,
configure the
BurFlags
registry key, and then restart the FRS service. To do so:
- Click Start, and then click
Run.
- In the Open box, type
cmd and then press ENTER.
- In the Command box, type net
stop ntfrs.
- Click Start, and then click
Run.
- In the Open box, type
regedit and then press ENTER.
- Locate the following subkey in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NtFrs\Parameters\Backup/Restore\Process
at Startup
- In the right pane, double
click BurFlags.
- In the Edit DWORD Value dialog box, type
D4 and then click OK.
- Quit Registry Editor, and then switch to the
Command box.
- In the Command box, type net
start ntfrs.
- Quit the Command box.
When the FRS service is restarted, the following actions
occur:
- The value for the BurFlags registry key is set back to 0.
- Files in the reinitialized FRS replicated directories
remain unchanged and become authoritative on direct replication, and through
transitive replication, indirect replication partners.
- The FRS database is rebuilt based on current file
inventory.
back to
the topGlobal vs. replica set specific reinitialization
There are both global- and replica set-specific
BurFlags registry keys.
Setting the global
BurFlags registry key reinitializes all
replica sets that the member holds. Do this only when the computer holds only
one replica set, or when the replica sets that it holds are relatively small.
In contrast to configuring the global
BurFlags key, the
replica set
BurFlags key
permits you to reinitializes discrete, individual replica sets, allowing
healthy replication sets to be left intact.
The global
BurFlags registry key is
found in the following location in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NtFrs\Parameters\Backup /
Restore\Process At Startup
This key can contain the same values as those that are
discussed earlier in this article for authoritative and nonauthoritative
restores.
You can locate the replica set specific
BurFlags registry key by
determining the GUID for the replica set that you want to configure. To
determine which GUID corresponds to which replica set and configure a restore,
follow these steps:
- Click Start, and then click
Run.
- In the Open box, type
cmd and then press ENTER.
- In the Command box, type net
stop ntfrs.
- Click Start, and then click
Run.
- In the Open box, type
regedit and then press ENTER.
- To determine the GUID that represents the replica set that
you want to configure, follow these steps:
- Locate the following key in the registry:
KEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NtFrs\Parameters\Replica
Sets
- Below the Replica Sets subkey, there
are one or more subkeys that are identified by a GUID. In the left pane, click
the GUID, and then in the right pane note the Data that is
listed for the Replica Set Root value. This file system path
will indicate which replica set is represented by this GUID.
- Repeat step 4 for each GUID that is listed below the
Replica Sets subkey until you locate the replica set that you
want to configure. Note the GUID.
- Locate the following key in the registry:
KEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NtFrs\Parameters\Cumulative
Replica Sets
- Below the Cumulative Replica Sets subkey,
locate the GUID you noted in step 6c.
- In the right pane, double click
BurFlags.
- In the Edit DWORD Value dialog box, type
D2 to complete a nonauthoritative restore or type
D4 to complete an authoritative restore, and then click
OK.
- Quit Registry Editor, and then switch to the
Command box.
- In the Command box, type net
start ntfrs.
- Quit the Command box.
back to
the topConsiderations before you configure authoritative or nonauthoritative restores of FRS members
If you configure an FRS member to complete an authoritative or
nonauthoritative restore by using the
BurFlags registry subkey, you do not
resolve the issues that initially caused the replication problem. If you cannot
determine the cause of the replication difficulties, the members will typically
revert back to the problematic situation as replication continues.
A
detailed breakdown on FRS interdependencies is beyond the scope of this
article, but your troubleshooting should include the following actions:
- Verify that Active Directory replication is successful.
Resolve Active Directory replication issues before you perform additional FRS
troubleshooting. Use the Repadmin
/showreps command to verify that Active Directory replication is occurring
successfully. The Repadmin.exe tool is located in the Support\Tools folder on
the Windows 2000 CD-ROM.
- Verify that inbound and outbound Active Directory
replication occurs between all domain controllers that host SYSVOL replica sets
and between all domain controllers that host computer accounts for servers that
participate in DFS replica sets.
- Verify that FRS member objects, subscriber objects and
connection objects exist in the Active Directory for all the computers that
participate in FRS replication.
- Verify that inbound and outbound connection objects exist
for all domain controllers in the domain for SYSVOL replica sets.
- Verify that all the members of DFS replica sets have at
least inbound connection objects in a topology to avoid islands of
replication.
- Review the FRS and SYSTEM event logs on direct replication
partners that are having difficulty.
- Review the FRS debug logs in the
%SYSTEMROOT%\DEBUG\NTFRS_*.LOG between the direct replication partners that are
having replication problems.
For more information about troubleshooting FRS
, click the following article number to view the article in the Microsoft Knowledge Base:
249256
Troubleshooting intra-site
replication failures
back to the top