VMware Power Management or Distributed Power Management (DPM) powers down hosts when resources are not needed and powers the host on as the demand for resources increases. This feature has the potential to provide significant savings in power and cooling especially in a large cluster.
I recently implemented DPM on the VMware Lab at TCC, a 12 host cluster that is only utilized a couple nights a week for classes. When hosts are idle DPM powers them down (Standby Mode) and then powers them up during class times as student access VMs requiring additional cluster resources. With DPM enabled there are usually only 2 or 3 of the 12 hosts powered on outside of class hours when there is very little resource consumption . This greatly reduces the load on the UPS and the heat in the TCC server
After successfully getting DPM working in the school lab and a bit of testing I decided to set it up on my production environment. One difference between the school lab and the production environment (besides the size – 4 host instead of 12) is that I want ensure all of my host resources are available during business hours. I do not want to have to wait for hosts to power on when resources are needed especially at the start of the business day. This can be accomplished by configuring DPM and then setting up a vCenter Scheduled task to turn DPM off and on.
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