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I will be deploying 3 VMs on a 4 CPUs x 2.799 GHz (Intel Xeon W3530), 24GB RAM ESXi 4.1 server. They will be:

  1. Win 2k8 R2 with IIS Server, php web gui.
  2. Win 2k8 R2 with SQL Server 2008.
  3. Win 2k8 R2 with Java App using Hibernate.

my question is, what are your reccomendations as far as vCPUs and RAM for the setup?

EDIT: Given that I want to divide all the host resource only for these 3 VMs. What would be your setup?

Thank you very much.

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Start with the minimum system requirements for RAM and CPU for the OS and applications and go from there. You can add vCPU's and RAM if needed.

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+1, the best thing about VMs is the ability to change hardware configuration on demand. Just use it. – Massimo Mar 2 '12 at 11:56
Actually I was put off by this warning: changing the number of virtual processors after the guess OS is installed may make the virtual machine unstable. – JoeSlav Mar 2 '12 at 12:14
It's pretty simple to add a vCPU as Windows will automatically install the appropriate HAL driver (going from uniprocessor to multiprocessor). Going in the reverse direction is a little more challenging (from multiprocessor to uniprocessor). – joeqwerty Mar 2 '12 at 12:44
I would never configure a VM with a single virtual CPU. For one thing, the MP version of modern OSes tends to be more stable. For another thing, it creates possible conversion pain. – David Schwartz Mar 2 '12 at 15:38
@DavidSchwartz - that's a horrible recommendation. For many single-task VMs, adding a second vCPU just adds overhead and is a waste of hardware resources. Your comment goes against many vmWare best practice docs. – Jim G. Mar 2 '12 at 19:22

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