> Classic DIY NAS builds consume outrageous amounts of power (35W to >100W) compared to commercial NAS (~10W)
??
Commercial NAS (like non-RM Synology & friends) are not magic. They save a bit of power due to higher system integration, yes, but most power is saved simply by using low-end hardware.
Most x86 DIY NAS use either desktop hardware or low-end server hardware (usually same thing, different labels) -- most of these have far more compute power than the small Atom C2000 or similar found in a x86 NAS.
If you want something similar to a commercial NAS, then use low end Mini-ITX boards (<10 W TDP, usually four SATA ports and perhaps one PCIe) or a PCEngine.
ARM boards on the other hand are all rather weak in all regards: poor I/O, little memory, weak CPU cores (even if there are four of them), quite some of these boards also have stability issues. None have ECC.
Who said anything about magic - a) they don't use x86, b) they use boards with few unnecessary peripherals, and c) their vendors are perfectly fine with proprietary drivers (-> can't easily reuse their HW).
Good luck doing a build with an overall 10W consumption target with x86 and what is essentially desktop HW, especially if it should be affordable (relative to a ~250€ commercial solution) and maintainable (no, no custom kernels with weird patchsets that rot away in 6 months, and having to recompile the world).
We have used PCEngine boards. They're fine as network appliances. But even the latest ones only have 1 SATA port (fine, 2 if you count the mSATA port).
I ran an E-350 (20 W TDP) based board for many years and without the idling drives (each about 0.5 W; only system SSD connected) it consumed about 7 W idle. That's well within your 10 W figure - and boards with lower TDPs are available as well (though a lower TDP does not generally imply lower idle power).
The replacement system (Sandy Bridge i3) pulls about 25 W in the same scenario, which is fine by me.
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Now you're saying that 10 W with desktop hardware is not possible, and yeah, that'll be difficult. But it's a false dichotomy: the "10 W commercial NAS" doesn't have anywhere near that capable hardware. You can absolutely achieve these power consumption levels with similarly spec'd hardware.
I have a Netgear ReadyNAS NV+ rev. 1 (got it for free from work) with a 200mhz SPARC processor. Revision 2 of the "same" product is based on ARM. Modern ReadyNAS desktop lineup though? Atoms and Pentiums!
??
Commercial NAS (like non-RM Synology & friends) are not magic. They save a bit of power due to higher system integration, yes, but most power is saved simply by using low-end hardware.
Most x86 DIY NAS use either desktop hardware or low-end server hardware (usually same thing, different labels) -- most of these have far more compute power than the small Atom C2000 or similar found in a x86 NAS.
If you want something similar to a commercial NAS, then use low end Mini-ITX boards (<10 W TDP, usually four SATA ports and perhaps one PCIe) or a PCEngine.
ARM boards on the other hand are all rather weak in all regards: poor I/O, little memory, weak CPU cores (even if there are four of them), quite some of these boards also have stability issues. None have ECC.