You might be surprised how little power it’s sipping when sitting idle. Unnecessary disk accesses might be the biggest power use in those hours, but that’s more likely to cost you due to wear and tear and eventual replacement of the drive.

I recommend buying a Kill-a-watt and monitoring your power consumption on the server for a week or two. Then do some math to see how much it’s actually costing your energy bill. If it’s actually considerable, then try using tools like powertop to see if you can determine what’s generating all the activity.

power top is a helpful program to monitor power consumption on some hardware, alsk funny name

Try testing TLP in battery mode even if you’re not using a laptop. You can configure all kinds of things to your liking with it.

I tried it out a few years ago and none of my server apps showed any noticeable decrease in performance with it running, but my power monitoring plug did show a reduction in power consumption. I ended up leaving it enabled all the time.

Mine shuts down while im asleep and while im at work. I only use it in the afternoon.

I split my loads (gigity) between the power hungry NAS and a passively cooled low power Proxmox host.

For me, most 24/7 activities are low CPU - like Home Assistant, so it needs to be there, but it doesn’t need to do anything.

Other VMs are ansible, uptime kuma, smokeping, etc… the most they use is RAM

Then the (relatively) more power hungry NAS powers up 3 times a day to syncthing everything, maybe upload a backup, and if no-one’s using Immich, etc. then it’ll power back off again.

The only other thing I have yet to downsize is my pfSense box (still a low powered device, but has fans…) and a Raspberry Pi I use for my Zigbee network.

Downsizing. If you don’t need to run or keep stuff, then you don’t need so many servers and storage. You may run stuff on cheap mini-pcs.

Sleep: In my experience sleep sucks, I’ve spent long hours planning around sleep in homelab, like: when do I restart, do updates, when do I upload backups. I have Pi and at some point I realised some actions on Pi need my sleeping NAS… so I dropped all the sleep and now it works 24/7.

Just yesterday I found this video talking about this very topic: https://www.youtube.com/watch?v=MucGkPUMjNo

When I built my NAS I intentionally bought the latest gen cpu, but kept it in to the 65W series with a GPU chip onboard. It’s an AMD Ryzen 5 7600 6-Core @ 3800 MHz. My coral usb does frigate and the integrated graphics chip does jellyfin just fine. I started with ssds, but half of them burned out pretty quick, so I replaced them with spinning rust. But, as-is it can run for an hour on my desktop grade UPS before it shuts down. My proxmox cluster is old laptops that mount an NFS drive from my NAS. So, yes, I took power efficiency into account.

spinning-down hdd’s when they’re not in use

I’ve just been through this recently. I decided to have my 2 backup HDDs spin down when not in use (99% of the time). I ran into an issue though where I needed them to wake up for SMART tests (which SMART didn’t trigger). Tried a few things that didn’t work so just set them to spin all the time. There’s about a 1-2w difference when they’re spinning all the time. So it’s just not something worth worrying about IMO (In the UK with high energy costs that comes out to 2.5 pence per day roughly).

As someone else here mentioned, isknf powertop can significantly reduce consumption at idle, which helps.

In the world of servers, though, unless a device is only accessed once a day, it’s tough to get the HDD to spin down.

I made a post about this a while back because I had some of the same concerns about power usage. (https://lemmy.world/post/41185625)

As most people are telling you, as they told me, ‘get better, more efficient equipment’, which is great advice if you are buying, but not so helpful if you’ve already bought. First thing I’d do is get a watt meter to get a baseline of what is being consumed. You can get watt meters from Amazon, or your preferred big box vendor, for cheap.

Once you have the baseline, then you can go about fiddling with Linux and your server, to find areas of excess power consumption. Please note tho, you’re not going to tame a $100 a month server down to $20. That’s just outside the realm of reality. However, every little bit helps. Go into your BIOS and check if there are power saving options there as well.

I know this will go against the grain, but I have a cron that powers off the server every evening before I retire. I am the only user of my services and I have no midnight, mass Linux ISO downloads going on, so I couldn’t justify having the server run for 10+ hours idle, consuming electricity. Electricity here is fairly cheap and I also have solar panels, but still, I think it’s worth the effort to be prudent with your resources.

In the end, the final tally was that I spend around $35 USD per month in electricity, which is far less than most people spend on a hobby.

Newer hardware that has lower idle consumption mostly. I’ve found there’s not much to do on a typical setup as far as software optimization, as most OS’s are already set up for pretty low power usage while idle.

HDD sleep can work if you don’t have anything accessing the drives, but with all the stuff running on my server there’s basically always some kind of activity going on so they never sleep. Less HDDs is the answer for me, I just have 2 large drives in a ZFS mirror.

My HP box with an i5-7500 idles around 15-20W which is decently low, but I also have 2 PCs with i3-7100u mobile chips that idle at 1-2W with 32GB of RAM and an NVMe SSD, which is wild.

Avoiding enterprise gear is key, it’s extremely power hungry.

My video server runs from 6 pm to 1 am. No need to run always.

I got a power-efficient mainboard and PSU. I think that’ll be the lion’s share. And I don’t have any unnecessary stuff like a GPU or extra stuff connected.

I ran powertop and adopted the recommendations to set the various buses, peripherals and devices into powersave mode. That does a few Watts here and there. CPU of course is also allowed to save power when idle.

And then I made the harddisks spin down after 40min of not being used. Or something like that. So they’ll automatically spin down at night and when I’m not using them. As spinning hdds consume quite a lot of power if you have multiple of them and compare it to the 15-20W or so the rest of the computer uses. The operating system is on a SSD.

Added solar and a battery. I don’t worry too much about the power use as a result.