How do you build a 67TB file server for a fraction of the cost of commercial solutions? The people at low-cost backup service Backblaze have pulled it off, and they've posted a detailed guide complete with a 3D model of their custom 4U enclosure.
A single Backblaze server costs only $7,867, and it includes 45 1.5TB Seagate hard drives, four SATA controller cards, two power supplies, 4GB of RAM, six fans, and nine "multiplier backplanes." This contraption runs Debian Linux 4 using IBM's JFS file system and three RAID-6 volumes. Since RAID 6 uses two parity drives per volume, each 4U system should have a total 58.5TB of redundant storage.
The enclosure looks like so. (The fire-engine red paint job apparently comes as standard.)
For reference, Backblaze says a petabyte's worth of hard drives costs $81,000. Using all of those hard drives with this custom solution adds up to $117,000 per petabyte, while with the cheapest commercial solution the firm found, Dell's PowerVault MD1000, it would add up to a whopping $826,000.
Why share the design? Backblaze explains, "Our hope is that by sharing, others can benefit and, ultimately, refine this concept and send improvements back to us. Evolving and lowering costs is critical to our continuing success."