Hi,
I think there is a bit confusion about how to use I/O Analyzer in your I/O scalability test.
I/O Analyzer VM itself is I/O load generator. Even though you select your windows VM in Web UI, you cannot generate I/O from your specified VM unless it is an I/O analyzer VM. If you want to generate I/Os from 32 VMs, we may want to deploy 32 I/O Anlayzer VM (or cloning them) and choose one of them as controller VM.
If your windows VM already has I/O load gen or real workload, you can just use "listening mode" to collect ESX host I/O stats.
Thanks.