Ask HN: Always on low power home server

The RK3399 series boards are seriously overlooked. Generally speaking you get excellent hardware support (including display graphics) with either the "vendor supported" 4.4 series kernels with Mali blobs OR 5.x mainline whatever and recent Mesa. The 5.x/Mesa stuff is about as open as you're going to get with ARM SBCs and supports hardware acceleration up to 4K. So does the 4.4 stuff with Mali blobs but that also supports hardware encoding/decoding of various video codecs. It's the most "usable" desktop I've seen yet from an ARM SBC. Anyway, because this is about a home NAS...

I currently have an even cheaper RK3399-based Radxa RockPI 4B booting Armbian (Debian Buster) from a 250GB Samsung 970 EVO:

  kris@kkrock:~$ uname -a
  Linux kkrock 4.4.213-rockchip64 #19 SMP Sun Feb 14 22:42:42 CET 2021 aarch64 GNU/Linux
  kris@kkrock:~$ lsblk
  NAME        MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
  zram0       252:0    0   1.9G  0 disk [SWAP]
  zram1       252:1    0    50M  0 disk /var/log
  nvme0n1     259:0    0 232.9G  0 disk 
  └─nvme0n1p1 259:1    0 232.9G  0 part /

  kris@kkrock:~$ time dd if=/dev/zero of=testfile bs=1G count=10 oflag=direct
  10+0 records in
  10+0 records out
  10737418240 bytes (11 GB, 10 GiB) copied, 13.6438 s, 787 MB/s

  real    0m13.794s
  user    0m0.000s
  sys     0m6.880s

I suspect 5.x is probably a bit faster for I/O (maybe not) but I don't care about the Mali blobs and I like hardware video encode/decode when I need it.

There are guides for your chosen board, distro, etc floating around to update the SPI flash with the correct Uboot to support booting from eMMC, NVMe, USB, whatever. Oh yeah, the Radxa RockPi4 boards also support use of Odroid-style eMMC modules, which are really fast, readily available, and plenty durable. If using PCIe for anything make sure to apply the correct boot overlay to enable PCIe 2.0 support.

Depending on what you want to do between SD, eMMC, NVMe, PCIe/SSD, and USB3 there are plenty of options for storage.

The boards are available from Amazon and elsewhere but for the best pricing and accessory options use "Allnet.China". It took them a few weeks to get me my aluminum case and NVMe expander but it was well worth it:

https://shop.allnetchina.cn/collections/frontpage

They also have SATA hats, PoE hats, all kinds of other stuff to expand this little-known series of boards for various NAS options. Pretty much no matter what you do all in with case, power supply, storage options, etc you can't exceed $150 for valid configurations (excluding storage). My setup was around $100.

For thermal management I use their "Eco Pi Pro" aluminum housing with Noctua NT-H1 thermal paste. After an extended period running "stress" to peg all CPU cores this is what armbianmonitor shows (fanless):

  Time       big.LITTLE   load %cpu %sys %usr %nice %io %irq   CPU  C.St.
  15:37:24: 1800/1416MHz  6.25 100%   0%  99%   0%   0%   0% 57.8°C  0/5

Under 60 deg C fanless during an extended stress test? Not bad, not bad at all.

EDIT: Gave up on HN formatting. You get the point.

You can use a older possibly partially broken laptop with low TDP CPU. Put the guts in a larger PC case or something similar. You can calculate what kinda heat sink you need that works without fan or pick a fan-less device. You still need a bit air flow so the case must be open enough or has fans depending on the CPU and size. The last time I did this was several years ago and It was running 24/7 for about 2 years without any problem. A Laptop alone likely would dies someday because the fan dies. On idle the my whole system inclusive power supply was burning less than 10 watts.

But there are far far more efficient CUPs noways. You basically have the last 10 years of mobile CPUs to find something that does exactly what you need. Some older CPUs you can get almost for free. If you need something newer (with 4k video HW rendering an stuff) you may get a good dead with broken stuff. especially display and keyboard can be broken since you wont need them. make sure it has the IO you need especially RJ45 are sometimes missing on the very slim new devices Be aware that some devices can not be turned on without keyboard attacked! Either because the bios doesn't like it or more likely because the power on button is on the keyboard so an USB keyboard wont work! Also auto boot after power-lose may not be possible because some bios just do not have that option. So make sure you know exactly what you need first.

DO NOT (AB)USE THE LAPTOP BATTERY AS UPS. The battery will die within months if its always connected and all you get is a potential for a house fire.

Intel NUCs are pretty good if you want something a bit more powerful than a Pi. Very small form factor and low power usage. Low-end ones start at about $180[1]. There are also kits for a bit less if you want to supply the SSD and RAM.

[1] https://www.intel.com/content/www/us/en/products/boards-kits...

What’s your OS? Are running plane Linux or some NAS variant?

Ultimately, OP was looking for a low power server without relying on a MicroSD. So no, it's not strictly an alternative to a Raspberry Pi because once you boot from USB, MicroSD durability is no longer the issue.