Load-testing tools for Active Directory?

Are there any tools out there that can torture-test and measure AD performance? We're looking at a fairly major expansion of our environment (think tens of thousands of computers) that will throw lots of transactions at our AD environment.

We suspect that we need to add hardware to our core network, but I don't want to buy hardware blindly and either waste money or hurt performance for the users.

Any ideas? I'm thinking of a tool to generate synthetic transactions, but I'm willing to accept any suggestions.

Solution 1:

Microsoft has a tool exactly for this called Active Directory Performance Testing Tool (ADTest.exe). Unfortunately, I can't find any documentation online for you, but a quick adtest.exe /? should give you some information. I believe there is a "quicktest" option too which will get you up and running quickly.

You may also want to read this article on domain controller capacity planning. It is written for 2003, but it should apply to 2008 also.