Power Consumption: ESXi Home Lab

One of the bigger questions that I’ve always gotten about my builds is what is my energy consumption.  That’s something I’ve always been able to estimate, however, I’ve never taken the time to actually watch the wattage load with my Kill-a-Watt, or anything else.  Primarily because my lab is also a production lab, it very rarely comes down for any amount of time.  Last night gave me that opportunity.

Battery-iconBattery Backup for ESXi: APC BR1500G and APC BR24BPG

My lab had been running on an older, rackmount UPS that I had picked up off eBay, and although a solid UPS, it was feeling its age, and most likely needed some new batteries.  Instead, I decided to upgrade, and caught a couple of items on sale at Amazon: the APC BR1500G BACK-UPS Pro 1500 and APC BR24BPG Back-UPS Pro External Battery Pack that goes with it.  Although I don’t have a lot of power losses here, ESXi does take some time to suspend everything and get shut down properly, so I wanted a long run time.  These fulfilled that, and admirably.

ESXi Home Lab Power ConsumptionPower Consumption on ESXi Home Lab Builds

Building out my home lab, I had a number of “rules” that had to be met before a build was successful for the nodes.  The list is below, but one of those was simply that it had to be energy efficient.  I can go on eBay and pick up Dell 2950s all day long cheap … but they are power hungry beasts, and the resulting electric bill will far out-strip any savings that I find.

  • Nodes must use consumer grade hardware that also allow access to PCI Passthrough, Fault Tolerance, vMotion, and all other extended ESXi abilities, or server-grade hardware that is cheap and easily aquired (such as the Intel Pro/1000 Dual Gigabit PCI-X network cards I use)
  • Hardware must be easy to acquire
  • Nodes must be energy efficient.  Idle wattage ideally needs to be <150 watts

apc-logoDiscovering ESXi Energy Consumption with APC PowerChute Software

APC includes a piece of software for free with their UPS Battery Backups that monitors your energy usage.  It will even allow you to input your cost per kw/H and it will give you the cost per month (the longer it runs, the better) that everything hooked up to it costs.  In addition, it will shut your computer down when it’s low on power.  You can also set this up to automatically suspend your VMs and shut down your ESXi nodes, but that’s for another article.

As I was switching everything else last night, I decided to plug in just a single node, and double-check my power consumption, and then take a look once everything was online.  If you haven’t read my ESXi Home Lab Specs, then I would suggest you do.  Currently, I’m running three ESXi nodes, two DLink DGS-1124T 24-Port Gigabit Smart Switches, a Juniper SRX100 firewall, a Juniper SSG5 firewall, a Netgear WNR3500L running DD-WRT, a vCenter/Starwind iSCSI box, and a Motorola Motorola SB6120 SURFboard modem all of the UPS.  The UPS with the battery pack performs admirably, and gives me plenty of runtime.

The APC series of UPS come with a data cable that allows you to plug into a USB port and monitor the UPS, as I said.  In my case, I have it monitored by my standalone vCenter/Starwind iSCSI box, since this box is doing little beyond that work.  The box is running the cheapest AMD dual-core CPU, and still doesn’t have any issues performing it’s assigned workload.

ESXi Home Lab Power ConsumptionActual ESXi Node Power Consumption vs. Lab Power Consumption

To test my power consumption, I brought up a single ESXi node first.  This node has the ASRock 970 Extreme3 motherboard I prefer, a Intel Pro/1000 Dual Gigabit PCI-X network card, a generic PCI-e Gigabit network card (I use a total of 4 Gigabit NICs per node), and a Hitachi Ultrastar 3.5-Inch 2TB 7200RPM SATA III Enterprise Hard Drive, a drive I’ve been using for years with excellent results.  If you’d like to see the specifics of the build, you can see it here.

Power consumption for the node was almost spot on to my calculations, with the node idling at 121 watts.  One thing to remember is that this IS idle.  Although your consumption wouldn’t go up much at full load, if you’re folding or number crunching 24/7, you’ll see a difference on your electric bill that you’ll need to be aware of.

Power Consumption: ESXi Home Lab Node

Power Consumption: ESXi Home Lab Node

Power consumption with the entire node online was right around my calculations also.  The Dell DGS-1124T 24-Port Gigabit Smart Switches are green and draw around 9 watts each, the modem and router draw about the same, and even my primary ESXi node which has a large number of hard drives in it, only draws about 50w more than this.  You can see that build at ESXi 5.0 AMD Whitebox Server for $500 with Passthrough (IOMMU)

The entire lab idles at just under 600 watts.  I consider that a success for 32 cores, 128GB of RAM, three ESXi nodes, two firewalls, two 24-port gigabit switches, and a standalone vCenter box that also functions as a iSCSI node.  At my current cost of .09 per killowatt hour, that puts my cost at $1.296 per day, $38.88 per month, or $473.04 per year.

  • RubenBM

    Thank you, Don, for sharing theses specs. I’ve been planning to make a few changes to my home network and would like to apply some of the concepts you’ve put in place. It would not be as much of a full-blown lab as you have deployed, but I think it’ll do the job.

    I’ll share my setup (as soon as I define it), and see what you think of it.


    • Thanks, Ruben, and you’re welcome. Would love to see your specs when you finish out! Good luck!

  • Matt Watson

    I am very interested in the power consumption of the Dell Poweredge 2950’s? I am looking at beginning to build a home lab myself.

  • Sebastian

    How much power do you think the ASRock build would use without disks and graphic cards? Thanks!