HomeLab Stage LXX: Power Consumption

My last episode HomeLab Stage LXIX: vSAN ESA was all about the new architecture within vSAN. This time I am talking about a complete different topic: Reducing Power Consumption!

As you might expect, the power consumption of my HomeLab is huge…. not every server or storage subsystem wihtin in HomeLab is running 24/7, but it consumes 30.000 kWh per year.

I was looking for ways to reduce my power bill (1.000€ per month). Powering off my HomeLab was not an option…. What other alternatives are available?

After speaking with specialists from Dell, Intel and VMware my decision was clear: Reducing the power and not shutting down anything. Why not throttle the systems at night to save power?

After investigating and doing a lot of research I have done the following for and within my servers:

My main cluster (HomeLab Stage LXVI: Monster Cluster) is equipped with two Dell R740xd servers, each with 1.5TB memory, Nvidia GPU, 100GbE, Optane Cache Disks and a lot of Capacity Disks.

UEFI settings:

System Profile Settings: (Custom, OS DBPM, C-States, C1E and Energy Efficient Policy)

Memory Settings: (Performance Mode)

SATA Settings: (Embedded Disabled) This saved 18 Watt!

Serial Ports: (Disabled)

I have modified the cooling option for my servers as well:

Slot 1 is equipped with my RTX8000 GPU, I disabled the Automatic fan control, to decrease the noise level.

ESXi Advanced Settings:

These are my modified Advanced Settings for power savings:

Please modifiy these values at your own risk. I spend several hours to find my optimal settings!!!!

All power settings apply only for the Custom Power Management Option.

Here is a screenshot of my Custom Option within esxtop: 453W, CPU Frequency max 1.4 GHz

I have modified my Frontpanel on my Dell Server to show the actual power consumption:

Here is a screenshot of my High Performance Option within esxtop: 579 W, CPU Frequency 2.7 GHz

Switching Power Modes automatically

I am using a PowerCLI script to automatically switch from High-Performance to Custom mode. This is done every night and it saves me a lot of power….

# Keys for the values needed for the ConfigurePowerPolicy method
$powerProfiles =  @{
    "High Performance" = 1 ;
    "Balanced"         = 2 ;
    "Low Power"        = 3 ;
    "Custom"           = 4
# Set the PowerProfile to the desired state
(Get-View ($vmHosts | `

That in combination with my new solar system should reduce my power consumption by half, which is awesome.

High Performance Mode = 614 Watt per hour, Custom Performance Mode = 426 Watt per hour

I am not shutting anything down, I am just reducing the performance of my servers. I can live with that 🙂

Once again: If you are using these tips and advanced settings: Use it at your own risk…..

Stay tuned for the next episodes