Wednesday, March 26, 2008

The Zettabyte File System (ZFS) : no limits

OpenSolaris …(and Solaris 10) implements ZFS filesystem as of c 2005/2006… ZFS is a 128-bit file system... … to give you an idea of the capability limitations of a 128-bit file system (hint: there are none):

-If a billion computers each filled a billion individual file systems per second, the time required to reach the limit of the overall system would be almost 1,000 times the estimated age of the universe.

- Project leader Bonwick said, "Populating 128-bit file systems would exceed the quantum limits of earth-based storage. You couldn't fill a 128-bit storage pool without boiling the oceans."[2] Later he clarified:

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 kilogram of matter confined to 1 liter 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.[10]

ZFS read/write libraries are available on Mac OS X Leopard (which ported ZFS to the Mac in 2007)… but it has to be installed by hand from the binaries. Sponsored by Google’s Summer of Code, there is work being done on a port of ZFS to Linux due out in 2008. There have been bugs, but it is used in enterprise offerings and has distinct advantages…

Unix is technically the king.

(btw, Roy Fielding was/is on the OpenSolaris Community Advisory Board members as of 2005/2006)

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