I love my
4 (nope, older than that!)
6-year old HP Microserver N40L. If you're willing to do some learning, it's great to build your own NAS.
Mine runs FreeBSD 11.0-RELEASE with:
- SanDisk 160GB SSD (internal, optical drive bay) boot disk
- 4x WD Red 4TB HDs (internal)
- 4x WD Red 4TB HDs (external eSATA-connected enclosure)
- 6GB ECC RAM
- HP Remote Access Card
- Generic ASMedia SATA add-on card, with 2x eSATA and 1xSATA ports (for later expansion)
The 8 spinning-rust drives are arranged as a single ZFS 'zpool', consisting of four mirrored-pairs ('vdevs' in ZFS-speak). So, 32TB of raw storage provides 16TB of actual storage. This has expanded over the years -- just added a pair of drives every 18 months or so.
The machine's easily able to saturate gigabit Ethernet reading and writing to the ZFS pool. Plus, it runs a Minecraft server and some other bits and bobs. FreeBSD 9.x and above are more than capable of automatically tuning ZFS to work with a given amount of RAM.
...and I went for ECC RAM because the server could use it, so why not!