I have been testing with the Microsoft Exchange 2010 Load Generator tool for the past month or so. I initially had some problems getting LoadGen 2010 beta to work well, so I thought that I would put together a quick blog post with the key things that I learned.
When changing the number of users in the mailbox databases or the size of the mailbox databases, you may need to first delete all the users. I found that when I tried to increase the number of users that had from an initially small number (about 100) to the number I was going to start testing with (4000) that I connection errors. These errors would occur when I tried to start the initialization of the users. I deleted all the users two different ways. I deleted and recreated the mailbox databases (hard way) and I set the number of users to 0 in LoadGen for all groups and let LoadGen delete the users (easy way).
Run the LoadGen 2010 Beta directly on the mailbox server VM for the initialization. This may actually be related to why I was having problems with changing the number of users. I initially started by doing the initialization from the load driver system I was also planning to run my Load Gen 2010 tests from. I found that the initialization went much faster by also installing the LoadGen 2010 Beta program directly on the Exchange mailbox server VM. I do the initialization on the mailbox server VM, but then switch to the load driver system to run the actual test.
Just reinitialize the users between each test instead of backup and restore of the mailbox databases. In previous tests with Exchange 2007 and LoadGen I initialed the mailbox database once it was initialized it, and then simply restored it before every test. The first initialization of users takes quite a bit of time, but subsequent initializations are much faster. I'm able to reinitialize 4000 users in about 30 minutes, which is faster than a restore in my case.
The documentation included with LoadGen 2010 beta is actually for the Exchange 2007 version of LoadGen. This is true for the included readme as well as the online help.
The best place that I have found with information on LoadGen 2010 beta is this post in the Exchange Team Blog - LoadGen 2010 (Beta Preview) now available.
I clearly cannot provide support for LoadGen 2010 beta, but I would be happy to try to answer questions based on my experiences.
Todd
