Hacker News Reader

Comment by melp | Hacker News Reader

Sits at about 250W, goes up to ~300W when it's running a scrub or something.

I generally run linux on my NAS, but power consumption is always one of my big priorities for my home NAS. I also shoot for the lowest possible idle power. I don't care if it consumes 250W when I'm using it, only that when I'm not using it it better be just a few watts. That is why i traditionally use Atom (c2000) or ARM hardware. Combined with disk spindown (custom script), turning off everything not in use (extra network ports, etc) My idle power is ~25W. I've only got 12 disks but the big power draw right now is the marvell SATA chips on my motherboard, which don't have any kind of link power saving controls (that I've found yet). I've got another motherboard using a G4400 that idles closer to 12W (total system power), but doesn't have ECC or a BMC..

Anyway, I use a little script which monitors activity against my MD device (yah software RAID, another discussion) and sends full spindown commands to the drives. I've been experimenting with a full drive powerdown, and full port power down (different machine). If I weren't using the NAS as a DHCP/DDNS/etc server I would probably put it into S3 standby and then wake it on CIFS/NFS/RPC inbound.

I'm also using cheap x540 based 10G boards, which add about ~5W a port, but I turn them off on an idle timer and fail-over to a 1G port that I can't measure the power on.

Bottom line, a home NAS device isn't a server that needs to run 24-7. Its not hard to tweak stuff to pull the idle power way down. Given a long enough timer (say 1-2 hours) you will only notice the machine resume/spin up once a day when you initially sit down at your desktop.

To put that in perspective it's roughly $0.60 a day, $18 a month and $219 a year USD assuming a rate of $0.10 per kilowatt hour [1] plus an additional 853 BTU/hr cooling load on the AC system [2].

[1]: http://www.rapidtables.com/calc/electric/electricity-calcula...

[2]: http://rapidtables.com/convert/power/Watt_to_BTU.htm

Rates in California would be double that or more, depending on which tier this put the user. For me, my old 8-cpu Xeon server cost me ~$50/month in electricity so I decommissioned it, however, this would also push me towards wanting to get solar panels for the house.

Did you consider a low power NAS approach? Spending somewhere around $20 per month on electricity for a home server seems like a lot to me. Maybe if it was hosting a handful of VMs for various purposes, but I suppose you don't want to run a NAS as a VM?

From what I've seen the nas is used for video editing, so you'll need fast access that only expensive internet connections can provide.

as a comparison, s3 for 60tb is $1600 a month.

well there are tradeoffs. If you want low power and high performance, you come down to choosing between either SSDs (very expensive) or a lot of laptop drives (cheap, but higher latency; throughput for something like video is fine though as you can fit a lot of them in a chassis; switching from 8drive Z2 groups to mirrors gets you a 4x improvement in throughput, which completely negates the throughput disadvantage of 5400 vs 7200).

Nope, never considered low power. I really didn't want a CPU bottleneck when I move to 10Gb network interface. Running a NAS in a VM (at least FreeNAS) is highly discouraged, so I never considered that. I do, however, run several VMs on the NAS itself, which help to justify the overkill hardware I used.

Why not going for less but larger disks then? It would be more power efficient. You have consumer 8TB disks. Surely you don't need that many disks for performance. Pretty much any Synology NAS will saturate a 1GbE link.

Reply on news.ycombinator.com