Hey, so although I posted a thread some time ago asking about this, I finished building it and have been tinkering with it for the past few months.
I thought I would share some pictures, and my experience thus far.
Cost:
This box itself I picked up on sale for $90 CAD. I had confirmed working ram (4GB Crucial) sitting in my drawer at home, and the CAT6 cable and Seagate Firecuda 2.5" 1TB SSHD were about $110 CAD together. For 30 dollars I purchased an MLC USB drive with good reviews and decent advertised transfer speed (Transcend JetFlash 780) for the boot drive. In addition I picked up a WD Blue 3.5" 5400 RPM 1TB drive and Nexstar TX powered 3.5" usb 3.0 external HD enclosure for ~ $80 CAD. I also purchased a CyberPower 350VA UPS ($60 CAD) so that I wouldn't need to worry about power outages (they're rare where I live anyway). In all the cost was around $360 CAD. Technology isn't really cheap in Canada, sadly, but I feel I've gotten good value for money and learned a lot and had fun along the way.
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Build:
It's pretty difficult to think of a task easier than building these thin client/nettop PCs, as they are usually tool-free (or close to it) installations. Not much to say here. As this is actually intended for commercial use (signage etc.) it was probably a little less user-friendly than the current generation of NUC marketed at home use, but a bit of sweat and fiddling with the drive cage and 20 minutes were all it took to get to the point of installing OMV.
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Performance:
I had posted a thread in the General config forum about a high load issue on this box. I have yet to really pin down the source of this issue beyond something do to with the cpu/mem usage output displayed on a few pages in the OMV webui. Changing a few settings around (limit nginx to 1 worker process as the box is single core, install sysfsutils and raise scaling_freq_min to roughly 933mhz instead of 533mhz) which seems to have ameliorated the problem somewhat, but it does appear every now and again. I have Pi-hole DNSBL/DHCP server installed on the same box (no docker, virtualbox, anything) and this runs perfectly fine and generates virtually no load, so I'm kind of thinking there's something funny going on with the webui but just haven't33 had time to investigate further.
Otherwise performance is great, even when the box was loaded by the webui to values over 2, SMB/CIFS and NFS shares work great. Streaming x264 media is a flawless even when this strange load condition appears.
Drive temperature in the box has never risen above 42*C (and it was about 30*C ambient temp that day), and cpufreq-info reports even when I'm streaming videos to multiple devices that the processor is running at 933-1GHz (the full clock speed is 1.46GHz). With ClamAV on the RAM usage has not risen above 18% of 4GB.
I think this would be a great single bay NAS unit. If you could buy a few of these at a time it would be fairly simple to just hand them out to your friends or family and provide yourself a little location independent data redundancy (in return for read-only access to your media library?) I had seen them for similar prices on ebay, in my mind I view it as being only a slightly larger investment than an RPi/3 (with case charger and an EVO+ you're looking at close to $90 CAD anyway)
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Caveats:
There are only 2 usb 2.0 ports and only 1 single usb 3.0 port. The boxes do not come with wifi chip but they do have an available m.2 port. Who cares though, it's a nas.
There is a strange issue with the omv web-ui wherein sometimes the system information pages displaying cpu/mem usage will generate runaway load conditions exceeding values of 2.0
The unit is fanless, if you live in a very hot place it might not be suitable for your use
The technology is now a little dated (2014) and so power consumption could probably be more efficient, in addition the processor isn't going to wow anybody. Subtract three cores from an RPi/3, add gigabit lan and a sata 3.0 gbps port and you've got the NUC Kit DE3815TYKHE.
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If you happen to see one of these locally or online for a good deal, and want something to play with, I would recommend it. Not too shabby! The build quality is nice, the unit feels pretty solid. Has been running for a little over a month now and very stable.
Images are hosted on imgur, click for a larger version.
Cheers and let me know if you have any questions.
Thanks for all the hard work devs! Awesome piece of software you have here. Hope to help out somehow.
Cheers,
Drinks2go