Google File System paper

Three of Google's scientists have written a paper on the Google File System, the file-system custom-designed for Google's server-farm.

First, component failures are the norm rather than the
exception. The file system consists of hundreds or even
thousands of storage machines built from inexpensive commodity
parts and is accessed by a comparable number of
client machines. The quantity and quality of the components
virtually guarantee that some are not functional at
any given time and some will not recover from their current
failures. We have seen problems caused by application
bugs, operating system bugs, human errors, and the failures
of disks, memory, connectors, networking, and power supplies.
Therefore, constant monitoring, error detection, fault
tolerance, and automatic recovery must be integral to the
system.

272K PDF Link

(via Hack the Planet)