Sam Winslow

Building a NAS on a razor-thin budget

— Why let perfectly good drives go to waste?

Motivation

I’ve had a Synology DS218 NAS for about 7 years, and it hasn’t let me down once, but I found myself running out of space on a pair of mirrored 2TB drives. It has only 2 drive bays; upgrade options looked pretty limited unless I were to buy bigger drives and let the old ones sit on the shelf.

I am averse to creating e-waste if it can be avoided, and I have a few external drives from my graphic design/video production days laying around. Could I reuse those? Looks like I could attach a USB drive to the Synology, but won’t be able to do any redundancy/parity on it.

It would also be nice to have another device to tinker with and run some containers on, such as Postgres, the GitHub Actions runner, or scripts to pull backups from other sources.

So if I could find a cheap, low-power motherboard/CPU combination as well as a rack-mounted case to keep the device out of sight and out of mind in my short-depth 9U networking cabinet, building from scratch might make sense.

The components of a budget NAS.

Hardware

Total: $327

Reusing 0.5 Reusing 0.5" aluminum channel to adapt a 2.5" drive to 3.5"

The drive stack The drive stack

It boots! It boots!

Software

Thought about TrueNAS, but potentially overkill.

I might want to have containers running off the fast boot drive, and won’t nearly need all 500GB for the OS.

There is limited/no support for installing TrueNAS to a partition rather than a full disk or within a container.

No Unraid as it’s payware and I’m uneasy about the boot key method.

What do I really need? ZFS, Samba, containers, basic monitoring interface.

Decided to go with a distro and ecosystem I’m more familiar with, Fedora Server.

Step-by-step

  1. Back up files from the other NAS to various places, ensuring at least 2x copies. Some of these backups had to be gzipped because I’m not exactly rolling in free storage space.
  2. Install the drives, 3x2TB in our case
  3. Poke around in the BIOS to enable useful features like Wake on LAN
  4. Install Fedora Server on NVMe drive from live USB
  5. Configure the network interface and set up a static IP
  6. Enable Wake on LAN in the OS
    • ethtool -s enp1s0 wol g
    • nmcli connection modify enp1s0 802-3-ethernet.wake-on-lan magic
    • reboot
  7. Install OpenZFS (official docs)
    • Why ZFS? Snapshot recovery sounds like something you might not think you need until you do.
    • There’s a lot of fear out there about frequent kernel updates in Fedora causing breaking changes with ZFS. I think this is overblown/could be mitigated by being careful about backing up the boot disk. In my experiences in the JavaScript ecosystem, it’s often sensible to pin a dependency at a particular version, and it’s not a bad idea to do that here with the kernel version.
    • Step 7 in the guide addresses kernel compatibility: By default ZFS may be removed by kernel package updates. To lock the kernel version to only ones supported by ZFS to prevent this: echo 'zfs' > /etc/dnf/protected.d/zfs.conf
  8. Create a raidz storage pool (per this guide)
    • I created a raidz1 pool across sda, sdb, sdc (all 2TB drives), which should yield a capacity slightly less than 4TB and which can tolerate failure of at most 1 drive.
      • zpool create storage-pool raidz1 sda sdb sdc -f
    • This sounds less safe than a mirrored configuration, but is it really? In addition to the older desktop drives, I’m adding a 2TB drive that was used very infrequently, and my storage workload won’t require running the drives 24/7. I’m not convinced I would be any safer running heavily used secondhand WD Red drives from Ebay, even in raidz2, which was my other temptation.
    • The drives will still be colocated and there are plenty of things that could take them out all at once, like a power supply issue or a natural disaster. I should probably set up Backblaze for offsite backups.
  9. Set up a Samba share (Fedora docs)
    • Not doing any group stuff since I’ll be the only user for now
  10. Put all your files back, profit.

Conclusion

In a weekend and with just over $300 in hardware, I roughly doubled my available storage space for full-size photo scans, client work, and general backups. Sequential write speeds over SMB, which is the main way I access the device, got roughly 50% faster. I'm sure read speeds are similarly better, but I haven't profiled that yet.

What I lost in ease of use within the Synology ecosystem, I gained in flexibility and upgradability. The new NAS motherboard has good expansion capabilities for SATA and M.2 drives, and leaves just enough space for those future drives because of its small form factor.

4x 2.5GbE ports, which I consider the new standard for my home network, are nice to have. I get 1200Mbps down currently, and think this could increase, but I also think it’s unlikely that I will need 10GbE in the next five years or so. Maybe I could repurpose this box into a firewall at some point.

The NAS in its new home. The NAS in its new home.

Useful resources

Future plans

Thanks for checking this out!

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