DIY NAS

I've learned two things in the past: you can never have enough money, and you can never have enough disk space. Okay, there's a third thing i've learned: those two above are mutually exclusive. My first NAS was a Conceptronic CH3SNAS with two 1TB drives as RAID1 and a Gbit NIC. The existing OS on there was pretty soon "extended" with FFP to work around some issues and also provide access to the system's shell.

Having shell access taught me some things about off-the-shelf consumer NAS and their manufacturers:

• They're just using Linux, too
• They're stripping all the good stuff to optimize their system
• They're not good at optimizing

With these insights, the observation that the weak CPU of the CH3SNAS was not even remotely able to provide Gbit-bandwith (only ~20MByte/s) and the strong desire to have a more flexible storage solution, i decided to build my own NAS from off-the-shelf computer parts - and have never looked back.

What OS should i use?

My original idea was to basically just build a regular PC, just without any fancy graphics card, a cheap but reasonably powered CPU and loads of large drives, then put Debian Linux on there and just start from scratch configuring all the services like Samba and... well, actually i only needed Samba, but with decent performance.

No big deal and easily done, right? But then i discovered OpenMediaVault. Don't get, i'm more than capable of installing, configuring and maintaining my Linux systems, and happy to have something to tinker with, but OMV looked like it would be easy to use (compared to e.g. Openfiler) and by that i mean "keep me from tinkering too much with it, losing Terabytes of data in the process". And it was just a regular Debian Linux under the hood, so i'd still have all the freedom i want.

After 4 years of using it, i'm still convinced that going with OMV was the best decision, compared to the alternatives out there - and i tried a couple of them - so this would be my OS recommendation for everybody looking into building their own NAS, too.

Blockbox (2012)

• Motherboard: Asus E35M1-I
• CPU: onboard AMD E-350
• RAM: 2x 2GB DDR3 1333MHz
• SSD: OCZ Agility 3 60GB Samsung 840 128GB
• HDD: 6x WD Green 2TB WD20EARX
• Case: Lian-Li PC-Q08 black

The HDDs are configured in a RAID5 (mdadm) with ~9TB usage storage space and have been running 24/7 for the last 4 years. No failures at all. That can't be said of the OCZ SSD i was using for the OS, though. The CPU is more than sufficient to saturate the Gbit link when reading and writing to the disks and only shows only moderate load when Syncthing hashes new files (like my nightly backups, more on that later).

Overall this system is still more than sufficient, performance-wise. One could even say it is quite a bit over-powered for its purpose. Unfortunately it's also maxed out, storage-wise.

Back in 2012 i was confident that going from 1TB of available space to ~10TB would last me a lot longer than 4 years, but now (2016) i'm down to ~500GB space left, which brings me into the Danger Zone™ of <5%. So what are my options?

1. More disks: not possible, only 6 SATA ports on the board
2. Bigger disks: possible, but would require replacement of all 6 disks, which is quite expensive
3. New NAS: possible, also quite expensive

So the choice is between replacing all 6 disks with 6TB ones, which would cost roughly 1700€, get me ~27TB in RAID5 and limit my options for further expansion, or building a new NAS with fewer drives (3x 6TB), wich means less available space to start with (11TB in RAID5), but with more SATA ports, which means with a better upgrade path for the future, for about the same amount of money.

Considering the urgent requirement for more disk space, but not that much right away, i went for the new NAS.