06-02-2013, 02:51 PM
Zettabyte File System
1Zettabyte File.pdf (Size: 1.94 MB / Downloads: 204)
Scalable
Although we'd all like Moore's Law to continue forever, quantum mechanics imposes
some fundamental limits on the computation rate and information capacity of any
physical device. In particular, it has been shown that 1 kilogramme of matter confined
to 1 litre of space can perform at most 1051 operations per second on at most 1031 bits
of information [see Seth Lloyd, "Ultimate physical limits to computation." Nature 406,
1047-1054 (2000)]. A fully populated 128-bit storage pool would contain 2128 blocks =
2137 bytes = 2140 bits; therefore the minimum mass required to hold the bits would be
(2140 bits) / (1031 bits/kg) = 136 billion kg.
To operate at the 1031 bits/kg limit, however, the entire mass of the computer must be
in the form of pure energy. By E=mc², the rest energy of 136 billion kg is 1.2x1028 J.
The mass of the oceans is about 1.4x1021 kg. It takes about 4,000 J to raise the
temperature of 1 kg of water by 1 degree Celsius, and thus about 400,000 J to heat 1
kg of water from freezing to boiling. The latent heat of vaporization adds another 2
million J/kg. Thus the energy required to boil the oceans is about 2.4x106 J/kg *
1.4x1021 kg = 3.4x1027 J. Thus, fully populating a 128-bit storage pool would, literally,
require more energy than boiling the oceans.
How we use it.
• Frantic will have 72TB of storage on ZFS
• Three Sun X4500’s with 24TB each
• Massive amounts of storage for reasonable
cost
• Changed the way we looked at storage
Technical details
• Metadata allocated dynamically
• Uses 256bit checksums to ensure data
integrity
• Adaptive Endianness
• Copy-on-Write
• NFSv4/NT Style ACLs
• Variable Stripe Size - No RAID5 ‘write-hole’