To ensure that your Active Directory implementation is firing on all cylinders, you will need to perform regular maintenance tasks. The goal of this article is to outline some of the basic steps you will need to take in order to ensure that you AD is healthy.

  1. Make sure you are taking regular backups.
  2. Make sure that domain controllers are replicating data without errors. Replication is where multiple AD databases are synchronised and updated when changes are made to a particular instance of AD. It’s a relatively straight forward process, but problems can sometimes arise. For example, sometimes replication can be delayed when domains are spread across a WAN. You can use a tool called Repadmin to find out the status of a recent replication, as well as information about the servers involved.
  3. It is important to check the event logs. It is not unusual for there to be errors in the event logs during the boot; however, assuming the server has been running for several hours, the event logs should be clean (with the exception of a few system messages). It is also important to regularly check the event logs even if there isn’t a known problem. That way it will be easier for you to spot an error in the logs should one present itself.
  4. It is important to defragment your AD database at least once a year, or perhaps more frequently, depending on the size and complexity of the database. This will ensure that your AD database is performing at its best. Windows Server provides a database maintenance utility called Ntdsutil, which allows you to defragment your AD database, manage single master operations, and remove unwanted metadata from domain controllers that were removed but not properly uninstalled. Additionally, Ntdsutil allows you to reset the Directory Services Restore Mode Admin Password, which is necessary if a sysadmin leaves your organisation. This tool should only be used by experienced administrators.
  5. Another very useful tool that Microsoft provides is called Dcdiag. Dcdiag allows you to analyse the state of domain controllers and reports any problems. There are many different tests you can do with Dcdiag. For example, it allows you to test connectivity, security settings, servers, topology, as well as identify missing accounts. You should run this tool regularly and pay close attention to the error messages. If Dcdiag returns no errors, it is almost guaranteed that your Active Directory is healthy. While Dcdiag may be very useful in identifying errors on your network, it is not very intuitive to use.

Are there any good third-party solutions available to help monitor the health of Active Directory?

There are a number of commercial solutions which you can use to check the health of your Active Directory. For example, the Active Directory Health Check Solution, provides an intuitive way of monitoring important elements of your Active Directory. This solution can generate reports about DNS Servers, Disk space, CPU, Memory, replication and more.