I'm a complete VMware know-nothing, but I recently set up 4 VMs on ESXi. 3 of the VMs are very non-resource-intensive (a lightly used file server, a lightly used domain domain controller, and a VMware vMA host), and one is more resource intensive (a terminal server used by a dozen people in my small office).
The terminal server VM has been running quite slowly during peak hours. Taking a look at the performance summary in vSphere, it does seem that the CPU has been spiking above 90% quite a bit, My disk latency graph has some spikes in it too, occasionally going up to 500ms or so.
I have not configured any of the resource allocation settings in VMware, and always assumed that it would be smart enough to allow busier VMs to use available resources when less busy VMs didn't need them. It appears that this isn't the case, though, because the CPU chart for the overall server never spikes above 10%, and the disk latency never goes above 4ms or so.
So that tells me that perhaps I need to configure some of the resource allocation stuff in VMware, but I don't quite understand what I should configure in this situation. Should I increase the number of vCPUs or configure processor affinity? Or should I use the shares or reservation features? Essentially, I don't want to completely starve the other VMs of resources, but I do want the terminal server to be able to use the system resources that appear to be available.
Thanks in advance for any guidance.