[ale] DIY NAS vs Boxed NAS?

[Alex Carver]

Lots of votes for DIY NAS.

Assuming that I choose that route, I'd be aiming for relatively low cost
(not including the cost of the drives, that's a sunk cost no matter the
array).  To this end I don't need a machine that can transcode video,
run fifteen application servers, VMs, or much of anything else.  I just
need a box that can handle SMB/CIFS/NFS for file storage from remote
machines (mix of *x, Windows, Mac), can run rdiff-backup over ssh (some
of my smaller machines back up using rdiff-backup for simplicity), can
send me an email if something is wrong, has two or more Gigabit ports so
I can divide network streams (one coming from cameras on a VLAN, the
other coming from the other machines), and the ability to support plenty
of drives without much extra hardware (at least four plus an OS drive
without needing a SATA card, more SATA ports is better though).

I wanted to avoid hyperexpensive motherboards.  I did some searching
after all the input on this thread came in and most of the build guides
for DIY NAS boxes max out the system so much so that you can run Plex,
Xen, an email server, an IoT server, cloud synchronization and like
fifteen other things, none of which I want.  I just want a giant file
bucket.  I want to send big files/backups to the machine and, in a
reasonable amount of time, have those files stored to disk and done.  At
the same time, that much horsepower is also using a lot of electricity
so minimizing that load would be great if I don't actually need it.
That simplifies cooling as well as I'd be able to use passive cooling or
slow fans.

The build guides were using things like $600-$1000 motherboards from
Supermicro and such that had 10 GbE ports, one had SFP slots for fiber,
another used a Core i7 processor and 128 GB of RAM, one even had a
Radeon graphics card in it.  Half of them used over 100 Watts idle with
a significant chunk going to the motherboard rather than the drives.
Surely a simple file server does not need nearly that much horsepower to
take data from an Ethernet port and shove it through a SATA port to a
disk.  The most taxing application for this thing would be continuously
recording multiple camera streams using H.264 (around 100-200 kBps on
average) or MJPEG (500-600 kBps) to disk over one of its ports.

So for those of you that did DIY, how much horsepower did you seek out
for the system and how little can I get away with for the most basic
file serving application without drastically harming performance?