I made a rack out of some dumpster-dived supermarket shelves, lumber, a truck air filter and a forced draft fan. The thing doubles as drying cabinet for produce (mint, mushrooms, fruit etc.) by having the equipment in the top half of the rack followed by an air flow divider and 8 rack-sized metal-mesh-covered drying frames. From top to bottom the thing contains:

* D-Link DGS-3324SR (managed switch, €35)

* HP DL380G7 with 2xX5675 @3.07GHz, 128GB (ECC) RAM and 8x147GB SAS drives (€450)

* NetApp DS4243 (24x3.5” SAS array, currently populated with 24x650GB 15K SAS drives, €400)

* the mentioned airflow divider

* 8 drying frames

It is managed through Proxmox on Debian and runs a host of services including a virtual router (OpenWRT), serving us here on the farm and the extended family spread over 2 countries. The server-mounted array is used as a boot drive and to host some container and VM images, the DS4243 array is configured as a JBOD running a mixture of LVM/mdadm managed arrays and stripe sets used as VM/container image and data storage. I chose mdadm over ZFS because of the greater flexibility it offers. The array in the DL380 is managed by the P410i array controller (i.e. hardware raid), I have 4 spare drives in storage to be used as replacements for failed drives.

The rack is about 1.65m high, it looks like this (here minus the DS4243 array which now sits just above the air flow divider):

https://imgur.com/a/M4Lbf1K

In the not-too-distant future I’ll replace the 15K SAS drives with larger albeit slower (7.2K) SAS or SATA drives to get more space and (especially) less heat - those 15K drives run hot. After a warm summer I added an extra air intake + filter on the front side (not visible on the photos), facing the equipment. This is made possible by the fact that cooling air is pulled through the contraption from the underside instead of being blown in through the filter(s).

I chose this specific hardware - a fairly loaded DL380G7, the DS4243 - because these offered the best price/performance ratio when I got them (in 2018). Spare parts for these devices are cheap and easily available, I made sure to get a full complement of power supplies for both devices (2 for the DL380G7, 4 for the DS4243) although I’m only using half of these. I recently had to replace a power supply in the DL380 (€20) and two drives in the DS4243 (€20/piece), for the rest everything has been working fine for close to 4 years now.

On the question whether this much hardware is needed, well, that depends on what you want to do. If you just want to serve media files and have a shell host to log in to the answer is probably ‘no’, depending on the size of the library. Instead of using ‘enterprise class’ equipment you could try to build a system tailored to the home environment which prioritizes a reduction in power consumption and noise levels over redundancy and performance. You’ll probably end up spending about the same amount of money for hardware, a bit more in time and get a substantially lower performing system but you’d be rewarded by the lower noise levels and reduced power consumption. The latter can be offset by adding a few solar panels, the former by moving the rack to a less noise-sensitive location - the basement, the barn, etc.

As to having 19" rack equipment in the home I'd say this is feasible as long as you don't have to sit right next to the things. Even with the totally enclosed, forced-draft rack I made the thing does produce enough noise to make it hard to forget it is there.