This post is an update of the my 2020 home NAS setup. A few things changed since then, the most important the introduction of snapraid for the media and archiving portion of the NAS.
The hardware hasn’t changed much apart from a (preventive) hard-disk replacement; my admiration and gratitude goes to HP for building a solid computer that runs flawlessly for seven years now.
Bill of materials
The hardware hasn’t changed much since the last write-up: the HP proliant microserver gen8 with four mechanical hard drives (of varying sizes) and one flash drive running with Ubuntu 18.04 LTS. I didn’t attempt an OS upgrade because everything works fine, even newer Docker software.
Goals and considerations
The original post went into great length to justify the goals and non-goals for the NAS build, since there have been a few updates I’m writing the new list down here:
| Goal | Description | Solution |
| Function | The NAS serves as a network attached file system for home use; the NAS operates a few hours a day and is either off or in standby most of the time | Commodity hardware, open source software, modularity, keep it simple |
| Interoperability | Commonly used computer platforms should be able to access files on the NAS. Commodity hardware should be able to connect to the NAS. | Samba (aka Windows shares) on Ubuntu, USB, SATA. Connect LAN to Wifi router, does name resolution and time server. Access and manage with SSH. |
| Modularity | Hardware and software components should be interchangeable without redesigning the entire system | x86 PC platform, Linux, Docker |
| Control | I want to control which software is installed on the NAS and what it does | Ubuntu 18.04 LTS |
| Valuable data | Valuable data (correspondence, legal documents, memorabilia) requires a high level of protection against loss, corruption and theft. The data volume is low and justifies the extra effort. | MD RAID 1 with 4 hard drives, ext4fs with journal checksumming, periodic RAID scrubbing, manually assembled RAID, ECC RAM. Partition is encrypted with LUKS. Sign archives with par2archive. |
| Bulk data | Music and films. Partial loss is acceptable, total loss would be bad. Large data volume requires an affordable solution. | JBOD with snapraid (2 data drives, 2 parity drives) and mergerfs. |
| Noise | Noise should be low and tolerable | HDDs in standby, SSD as primary OS disk, write-mostly, lots of RAM, passive cooling |
| Cost | Use commodity hardware and free, open source software | 2nd-hand commodity hardware, hard disks instead of SSDs |
| Low maintenance | Avoid time critical maintenance | ufw firewall accepting connections only from internal network, no auto-updates, limited software, Docker, not accessible from the Internet. |
| Data safety | In case of hardware loss or theft unauthorised parties shouldn’t be able to access the data | dmcrypt with key on external device |
| Low power consumption | Power consumption should be in line with the server’s function | Components in stand-by most of the time, SSD, RAID in write-mostly |
| Compact | Physical NAS dimensions should be small; no space wasted | 2nd hand HP proliant microsever gen8 |
Discussion
The main uses of the NAS are:
- Watching videos with VLC over samba shares
- Storing backups
- Running a media server
- Donating computing power to research projects
The biggest change has been dividing the NAS into a data volume for valuable data and a data volume for bulk data, which is mainly my music and film collection and backups.
The volume for valuable data is an MD RAID 1 with 4 small-ish partitions on 4 hard drives (one partition on each hard drive). The volume is encrypted with LUKS and manually assembled with a script during boot.
The volume for bulk data consists of four large partitions on the aforementioned 4 hard drives. Snapraid [1] is a user-mode software RAID implementation which really shines with media archives. I prefer it over the previous RAID6 setup because:
- It optimally integrates hard drives of varying sizes
- Snapraid’s partial data availability fits my risk averseness profile better than mdraid’s all-or-nothing
- Data is available even if Snapraid fails to start
- It protects data against corruption
I run boinc, jellyfin kiwix and clamav in Docker containers mainly for the easy setup and dependency isolation.
[1] Snapraid
https://www.snapraid.it/
George's Techblog 