Hi, Rob here!
So you think there’s lingering objects in your Active Directory forest and you need to quickly get rid of them!? If so, read on …
This blog post is a 4 part series, so stay tuned in the next few months for remaining 3 parts of the series, including forest wide cleanup of lingering objects, cleaning one NC and a few tips and tricks.
A brief bit of history and background…
For about a decade now, since the introduction of Windows 2000 and Active Directory both CSS and PFE have been chasing and cleaning lingering objects. A lot of fiddling with ways to make the process easier has come to an end for now …Fear no more, ReplDiag is here!
ReplDiag, developed by Ken Brumfield, with testing and tweaking done by numerous people in the DS space is a result of both internal and customer involvement and work. To date, it’s a well-known tool in the community to help address the problem of lingering objects, quickly and efficiently. The tool, as great as it is, has logic built-in for troubleshooting replication issues as well.
Although there are great write ups of the phenomenon, official supported methods of how to attack the problem is very complex and prone to errors due to the complexity inherent in AD replication topologies. For these reasons, hence the reason ReplDiag was born. It’s here to help you! At the bottom of this write up, you’ll find information on the problem of lingering objects and ways to tackle the issue, using other methods. Despite the latter, a few of us remain, who are all about getting the job done quickly, efficiently and with less room for error. Brave, no… Smart, yes.
Currently, ReplDiag is available only via CodePlex. For those of you who don’t know what CodePlex is; it is Microsoft’s open source software depot maintained by the community for the community! The disclaimer is here and the philosophy remains just what it is, open source. This means, a community of internal, external developers, and testers help maintain the repository. At Codeplex, you will find ReplDiag, as well as an array of other useful tools, for everyday tweaking and fixing, free of charge.
Let’s dig in …
So now, before jumping in blindly, you’re going to want to troubleshoot first, and below are some approaches on how you can begin to utilize (and understand) the tool’s output.
ReplDiag is all about helping to diagnose replication topology stability issues, preventing where possible, and remediating the consequences resulting from those issues. ReplDiag by design ONLY looks at the forest as a whole as to ensure the integrity of the directory as a whole replication must be working across the entire forest. While it has often been brought up that this is not necessarily how many organizations are structured for administering AD, the administrative boundaries organizations impose DO NOT have anything to do with how the technology works. Thus to keep the technology working, organizations need to figure out some way of getting along, at least well enough just to keep replication working. This may also includes punching through some firewalls for administrative purposes so that a holistic view of AD topology stability can be gained.
There are a number of different error states that are analyzed for by ReplDiag and classified regarding whether or not they affect the stability of the AD infrastructure as a whole. Below is the list of potential errors identified, what they mean, and why they are important.
As can be seen from the above, there are several error states that can be encountered that prevent data from getting through the whole organization, none of which show up just by looking for error codes in “repadmin /showrepl”. Specifically, anything where the absence of the existence of a link is what is preventing replication and cannot be detected just by looking for failures on existing links.
All of the above stability impacting issues need to be fixed before proceeding with any sort of remediation of replication divergence related issues otherwise the issues will most likely recur.
This concludes the 1st in the series. See you next month for part 2 of the series on ReplDiag.