Windows Server 2003 – Replmon Support Tool Utility
Replmon is one of the most exciting tools in the Windows Server 2003 toolkit. I have a tutorial to get you started with Replmon. What I like about Replmon is the way that it combines business with pleasure and practical with theory. Before I explored Replmon I could not picture how Directory Replication works, with Replmon I can see precisely what data is replicated to which partition. The theory of Domain, Forest and Schema partitions come to life when you can actually see the topology and the links.
Topics for Replmon
- Reasons for Using Replmon
- Getting Started with Replmon
- First Look at the Replication Monitor
- Appreciating the Scope of Replmon
- Summary of Replmon
Introduction to Directory Replication
Replmon displays information about Active Directory Replication. In Windows Server 2003, Microsoft has improved upon Windows 2000 in two ways, reduced latency, and only replicating the attributes, which have changed and not the whole object. Both Windows 2000 and 2003 use the same components namely; multi master model, change notification and pull replication.
I declare a bias. I just love using Replmon for its own sake. What I enjoy is thrill of making replication happen, I enjoy seeing those USN numbers change. In case you are wondering, there are also sound business and troubleshooting benefits of getting comfortable with Replmon.
Replmon will give you clues why replication is not happening. Sift through Active Directory replication messages and find the last successful synchronization.
See what happens when you try and force replication. Does Replmon magically synchronize, or do you get a new meaningful error message?
If you do get replication errors, say when you run DCDiag, then force the KCC (Knowledge Consistency Checker) to recreate the topology.
Should you have the luxury of a large forest, Replmon will give you an understanding of how the domain controllers are joined by three separate rings. In multiple domain configurations you could experiment creating shortcut links.
Investigate if there are any complications with Trusts. Examine the trust relationships, within or between forests.
Discover more about the meta data, in particular the attributes of objects. Again I confess a bias as I need LDAP attributes for my VBScripts, Replmon displays the objects and their correct LDAP syntax.
Group Policies can be troublesome because there are two separate replication paths, Active Directory and FRS. Replmon also matches those strange hex numbers files which you find under sysvol, with the corresponding names of the policies as seen in the GPMC (or Active Directory Users and Computers)
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Installing Replmon is straightforward. Load the Windows 2003 CD into the caddy and navigate to the \support\tools and double click suptools.msi. However, a word of warning, because there are so many .dlls and associated Replmon files it is best to keep the files in their original locations. Of all of the support tools, Replmon is the fussiest about being run from its default location. A bonus of keeping all the support files in their default folder is that you can type the name of the executable in the Run dialog box and it will execute because the operating system has learnt the ‘Path’. Thus, in this instance type: replmon in the Run Dialog box.
Once Replication Monitor executes click on the Edit Menu and Add Monitored Server. Now follow your nose, and connect to the desired Domain Controller. If you have already used Active Directory Sites and Services to manually replicate Active Directory or to check on which servers hold Global Catalogs, then you cannot help noticing that the similarities between the interfaces. Note in passing, that as beginners we just focus on one site, however in a big organization there are likely to be several sites each with their own ring of linked servers.
Here in Replication Monitor, explore the 4 or 5 Configuration containers, keep looking for more detail by right-clicking on any object that you see. Below is an example of right-clicking the Domain Controller object.
Unlike other Windows Server 2003 tools where you can practice on just one Domain Controller, with Replmon you need two Domain Controllers to see any action. In fact the more Domain Controllers you add, the more you appreciate the clever ways in which replication functions. Best of all, if you have a multi domain forest, then you can trace the differences between domain and forest topologies.
Theory says that all domain controllers in the forest share the same schema, with Replmon you can actually see the one Schema ring containing every domain controller. Contrast the Schema ring with domain ring which has a separate ring topology for each domain.
My advice is to begin by right-clicking the ServerName object, from the resulting drop down menu select, ‘Show Replication Topologies’. As well as viewing how all the domain controllers are linked, this example shows the value of right-clicking on any object that you meet. At first it seems as thought there is nothing to see, but if you click on the View Menu, Connection Objects only, then all Domain Controller appear.
Hmm…. still no sign of the replication links. Let us try another right-click, and select ‘Show Intra-Site Connections’. At this point I pay attention to detail. I remember that Intra means within, whereas Inter is like Inter-City and means between. What you should now see is topology links between all the Domain Controller. Incidentally, the word ‘Site’ reminds us that to begin with, we are investigating just the Default-First-Site, in a production network there may be multiple sites.
If you have 5 or more servers in the ring, you may consider right-clicking and adding extra links to speed up replication; this is particularly true for Windows 2000 networks where latency is much longer than Windows Server 2003.
The best job for this free monitor is to check at a glance which of your servers are available. If there is a network problem you want an interface to show the scope of the problem immediately.
Even when all servers and routers are available, sooner or later you will be curious to know who, or what, is hogging the precious network’s bandwidth. A GUI showing the top 10 users makes interesting reading.
Another reason to monitor network traffic is to learn more about your server’s response times and the consumption of resources. To take the pain out of capturing frames and analysing the raw data, Guy recommends that you download a copy of the SolarWindsfree Real-time NetFlow Analyzer.
Active Directory Replication is a clever but complicated system. Microsoft’s Replmon enables you to see what is happening and where necessary, force replication or add extra links. Other benefits of running Replmon include troubleshooting Group Policy replication and examining trust relationships.
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