DFS Replication in Windows Server 2012 R2: Revenge of the Sync

DFS Replication in Windows Server 2012 R2: Revenge of the Sync
First released on TECHNET on Jul 31, 2013 This post belongs of the nine-part” What’s New in Windows Server & System Center 2012 R2 ” series that is included on Brad Anderson’s In the Cloud blog site. Today’s post covers DFSR and how it uses to the bigger subject of “Transform the Datacenter.” To check out that post and see the other innovations talked about, check out today’s post:” What’s New in 2012 R2: IaaS Innovations .”

Hi folks, Ned here once again. You might have read my post on DFSR modifications in Windows Server 2012 back in November and believed to yourself,” This is ok, however begin … this took 3 years? I anticipated more.”

We concurred.


Windows Server 2012 R2 includes considerable functions to DFSR in order to bring it in line with contemporary file duplication circumstances for IT pros and details employees on business networks. These consist of database cloning in lieu of preliminary sync, management through Windows PowerShell, file and folder repair from disputes and preexisting shops, considerable efficiency tuning alternatives, database healing material combining, and substantial scalability limitation modifications.


Today I’ll talk at a high level about how your service can gain from this enhanced architecture. It presumes that you have a previous working understanding of DFSR, to consist of standard duplication principles and administration utilizing the previous tools DfsMgmt.msc or DfsrAdmin.exe and Dfsrdiag.exe Everything I talk about listed below you can do today with the Windows Server 2012 …

I have a series of much deeper short articles too to get you rolling with more walkthroughs and architecture, in addition to lots of TechNet for the blog-a-phobic. Presently these are:

DFS Replication Initial Sync in Windows Server 2012 R2: Attack of the Clones

DFS Replication in Windows Server 2012 R2: If You Only Knew the Power of the Dark Shell

DFS Replication in Windows Server 2012 R2: Restoring Conflicted, Deleted and PreExisting files …

Database Cloning

DFSR Database Cloning is an optional option to the traditional preliminary sync procedure presented in Windows Server 2003 R2. DFSR invests the majority of its time in preliminary sync– even when administrators preseed files on the peer servers– taking a look at metadata, staging files, and exchanging variation vectors. This can make setup, catastrophe healing, and hardware replacement extremely sluggish. Multi-terabyte information sets are usually infeasible due to the prolonged setup times; the quote for a 100 TB dataset is 159 days to finish preliminary sync on a LAN, if efficiency is direct (spoiler alert: it’s not).

DB cloning bypasses this procedure. At a high level, you:

1. Develop a main server without any partners (or utilize an existing server with partners)

2. Clone its database

3. Preseed the information on N servers

4. Construct N servers utilizing that database clone

The existing preliminary sync part of DFSR is now immediate if there are no distinctions. If there are distinctions, DFSR just needs to capture up the genuine delta of modifications as part of a reduced preliminary sync procedure.

Cloning offers 3 levels of file recognition throughout the export and import processing. These make sure that if you are permitting users to change information on the upstream server while cloning is happening, files are later on fixed up on the downstream.

  • None – No recognition of files on source or location server. Fastest and most positive. Needs that you preseed information completely and do not enable any adjustment of information throughout the clone processing on either server.
  • Basic – (Default habits). Hash of ACL saved in the database record for each file. Submit size and last modified date-time kept in the database record for each file. Excellent mix of fidelity and efficiency.
  • Full – Same hashing system utilized by DFSR throughout typical operations. Hash saved in database record for each file. Slowest however greatest fidelity (and still faster than preliminary sync)

Some early test outcomes

What does this mean in genuine terms? Let’s take a look at a trial run with 10 terabytes of information in a single volume consisting of 14,000,000 files:

“Classic” preliminary sync Time to merging
Preseeded ~24 days

Now, with DB cloning:

Validation Level Time to export Time to import Improvement %
2– Full 9 days, 0 hours 5 days, 10 hours 40%
1– Basic 2 hours, 48 minutes 9 hours, 17 minutes 98%
0– None 1 hour, 13 minutes 6 hours, 8 minutes 99%

With the suggested Basic recognition, we’re down to 12 hours! Our 64 TB tests with 70 million files just take a couple days ! Our 500 GB/100,000 file small tests complete in 3 minutes ! I like exclamation points!

The Export-DfsrClone offers sample robocopy command-line at export time. You are complimentary to preseed information any method you choose (backup and bring back, robocopy, detachable storage, picture, and so on) as long as the hashes match and the file security/data stream/alternate information stream copy undamaged in between servers.

You handle this function utilizing Windows PowerShell. The cmdlets are:


I have a different post including a good walk through on this function.

Wait– did I state DFSR Windows PowerShell? Oh yeah.

Windows PowerShell and WMIv2

With Windows Server 2012 and previous variations, file server administrators do not have contemporary object-oriented Windows PowerShell cmdlets to develop, set up and handle DFS Replication. While a lot of the existing command line tools supply the capability to administer a DFS Replication server and a single duplication group, structure advanced scripting options for numerous servers frequently includes complicated output file parsing and looping.

Windows Server 2012 R2 includes a suite of 42 Windows PowerShell cmdlets constructed on a brand-new WMIv2 supplier. Companies gain from a total set of DFSR Windows PowerShell cmdlets in the following methods:

1. Enables the switch to modern-day Windows PowerShell cmdlets as your “typical language” for handling business implementations.

2. Can establish and release complicated automation workflows for all phases of the DFSR life process, consisting of provisioning, setting up, reporting and repairing.

3. Enables production of brand-new visual or script-based wrappers around Windows PowerShell to change usage of the tradition DfsMgmt snap-in, without the requirement for intricate API adjustment.

List all DFSR cmdlets

To analyze the 42 brand-new cmdlets offered for DFSR:

PS C: > Get-Command– Module DFSR

For additional output and description, usage:

PS C: > Get-Command– Module DFSR|Get-Help|Select-Object Name, Synopsis|Format-Table -Auto

We ensured to record every DFSR Windows PowerShell cmdlet online with more than 80 sweet examples, prior to RTM!

Create a brand-new two-server duplication group and facilities

Just to get your juices streaming, you can utilize DFSR Windows PowerShell to develop an easy two-server duplication setup utilizing the F: drive, with my 2 sample servers SRV01 and SRV02:

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