Category Archives: ActiveDirectory

DFS NameSpace Issues – Migrating From FSR To DFSR Following AD Upgrade

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I recently assisted a friend who had an issue with DFS Namespaces following an Active Directory Upgrade from 2008R2 to 2012R2.  They were faced with not being able to access the NameSpace following the demotion of the last 2008R2 controller and promotion of the final 2012R2 controller.

Upon opening the DFS NameSpace management console, the following error was displayed when selecting the required NameSpace – “The namespace cannot be queried. Element not found.”

After looking in the FRS (File Replication Service) and DFSR (Distributed File System Replication) event logs, I came to realise that the forest was using FRS for replication! This isn’t supported after 2008R2.  Ideally, you would have completed the migration from FRS to DFSR before upgrading the domain controllers.

Note: Always make sure you have a backup, snapshot or other reliable rollback method in place before doing anything in your live environment. This worked for me, it doesn’t guarantee it will work for you!

With FRS being the likely cause, I needed to confirm this.  I ran the following command to confirm the status –

Dfsrmig /getglobalstate

It returned the following result confirming that FRS was still in fact being used.

Current DFSR global state: 'Start'
Succeeded.

Before being able to look at the DFS NameSpace issue, this needed addressing.  Luckily you can still remediate this after upgrading the domain controllers. I would still advise confirming all the prerequisites are in place BEFORE upgrading!

Now onto the migration from FRS to DFSR.

Firstly, run the following command to move the state to the second of the four states.  The four states being; Start, Prepared, Redirected and Eliminated.

Dfsrmig /setglobalstate 1

You will then want to run a directory sync to speed things up, especially if you have a large replication interval!

Run the following RepAdmin command to get things moving.

Repadmin /syncall /AdeP

You can then monitor the progress by running –

Dfsrmig /getmigrationstate

You will then see any remaining domain controllers that are yet to have synchronized the new state.  Eventually you will see that all domain controllers have migrated to the second state; Prepared.

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Now time to move to the Redirected state.  Same process as the previous set but this time specifying ‘setglobalstate 2’

Dfsrmig /setglobalstate 2
Repadmin /syncall /AdeP
Dfsrmig /getmigrationstate

Again run the RepAdmin to get replication moving and monitor using the ‘getmigrationstate’ command.  As in the previous step, you will eventually see that all domain controllers have migrated to the third state; Redirected.

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Last one! Same as before, but this time you want to use ‘setglobalstate 3 –

Dfsrmig /setglobalstate 3
Repadmin /syncall /AdeP
Dfsrmig /getmigrationstate

Once complete you will get confirmation that you have reached the final state; Eliminated.

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You will now be able to run the ‘net share’ command to see that the SYSVOL share has been moved to ‘C:\Windows\SYSVOL_DFSR\sysvol’ and that the FRS Windows service is stopped and set to disabled.

Output of the ‘net share’ command
File Replication Service Properties (Local Computer) General Ing On Recovery Dependencies Service name Display name File Replication Service chronizas folders wth fila servers that use Fila Cation Service (FRS) instead of the newer OFS Path to executable C exe Startup type Service status Start Stopped Stop Pause Resume You can specify the start parameters that apply when you start the service Start parameters: *ppb'
File Replication Service (FRS) service

This should now give you a correctly functioning directory again! You will want to now check the Directory Services, File Replication and DFSR Logs in Windows Event Viewer to ensure you have no further errors.

Now onto repairing the NameSpace.  I read a few different blogs and guides for this, some included deleting the NameSpace via ADSI Edit others didn’t.

I found I didn’t need to delete anything, bonus.

The get the NameSpace accessible again I found that right clicking the NameSpace and removing it, followed by recreating it using the  ‘New NameSpace Wizard’ did the trick. 

OFS Management File Action View Window Help z[öl OFS Management v Namespaces Folder I Folder 2 Folder 3 (Domain-based in Windows Server 2008 mode) Namespace Namespace Servers Delegation Search New Folder... Add Namespace Server... Delegate Management Permissions... \smt- lab.IocaI\D New Folder... Replication Remove Namespace from Displaym New Window from Here Delete Refresh Properties Help a Add Namespace Server... Delegate Management Remove Namespace fr... New Window from Here Delete Refresh Properties Help
New Namespace Wizard Con Namespace Server Namespace Name and Settings amespace ype Review Settings and Create Namespace You have successfully completed the New Namespace Wizard Tasks Enum Task Creat Status e namespace
OFS Management File Action View Window Help zbll O d OFS Management v Namespaces Folder I Folder 2 Folder 3 Replication (Domain-based in Windows Server 2008 mode) Namespace Namespace Servers Delegation Search FSRoot Type Name Folder I Folder 2 Folder 3 New Folder... Add Namespace Server... Delegate Management Remove Namespace fr... New Window from Here Delete Refresh Properties Help

Upon recreating it, all of the folders reappeared and were accessible again with no additional configuration required. (these screenshots are of my lab, not the live environment as it was not appropriate)

Thanks for reading!

Exporting and Importing Active Directory OU Structures

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Recently I needed to build out some test Active Directory Forests that resemble production in order to complete some testing. One of the forests contained a significant amount of OU’s that I had no intention of manually recreating.

To run the New-ADOrganizationalUnit cmdlet, you need to provide the OU name and the Path where you want to create it. However, Get-ADOrganizationalUnit doesn’t provide the path, so you need to determine it from the DistinguishedName.

After a number of google searches, I couldn’t find exactly what I needed, so I began piecing together various bits of Powershell that I found. I ended up learning a bit of Regex in the process! Powerful tool if you know how to use it.

I came up with two versions in the end, you can see both below with the differences highlighted.

$OUs=Get-ADOrganizationalUnit -Filter * | select name,DistinguishedName,@{n=’OUPath’;e={$_.distinguishedName -replace '^.+?,',''}},@{n=’OUNum’;e={([regex]::Matches($_.distinguishedName, “OU=” )).count}} | Sort OUNum | export-csv C:\<Path_to_CSV>\OUTree.csv -NoTypeInformation
$OUs=Get-ADOrganizationalUnit -Filter * | select name,DistinguishedName,@{n=’OUPath’;e={$_.distinguishedName -replace '^.+?,(CN|OU|DC.+)','$1'}},@{n=’OUNum’;e={([regex]::Matches($_.distinguishedName, “OU=” )).count}} | Sort OUNum | export-csv C:\<Path_to_CSV>\OUTree.csv -NoTypeInformation

The first one effectively takes everything up to the first ‘,’ and replaces it with nothing, effectively removing the OU Name. The second one captures everything after the first ‘,’ and replaces the whole string with what was captured. Both have produced the same result in my scenario, but it was useful to understand both methods for future use of Regex.

Both also have a property called ‘OUNum’, this property counts how many time ‘OU=’ appears in the original DistigushedName string. OU’s need to be created in order, so that the parent OU exists before the child. This orders the OU’s in ‘tiers’ before exporting them to CSV. All OU’s in the root of the directory will get a value of 1, OU’s within these will get a value of 2 and so on. Credit to ‘David Z’ for this bit!

Once you have your data, you may or may not need to modify the domain. If you are importing it into a different domain, you’ll need to. In my case it was simple enough to do a find and replace in a text editor (eg. DC=lab,DC=local to DC=lab2,DC=local). You could look at using concepts from above to achieve this before exporting the data if you so wish.

Now you have your data, you need to import it. You can run the following in the target domain.

$OUs = import-csv C:\<Path_to_CSV>\OUTree.csv
ForEach ($OU in $OUs) 
          {New-ADOrganizationalUnit -Name $OU.Name -Path $OU.OUPath}

Hope this has been useful. Thanks for reading!