[tahoe-dev] erasure coding makes files more fragile, not less

David-Sarah Hopwood david-sarah at jacaranda.org
Tue Mar 27 22:57:13 UTC 2012


On 27/03/12 20:06, Zooko Wilcox-O'Hearn wrote:
> Where is the flaw in the reasoning?
>> The problem is the assumption that failures are independent.

No, this is the wrong way to think about it!

RAID-like systems are not trying to protect against correlated failures.
They are trying to protect against the subset of failures that are
uncorrelated. That is, it is not necessary to assume that *all* failures
are independent/uncorrelated, only that the subset that *are* is worth
defending against by use of redundancy.

-- 
David-Sarah Hopwood ⚥

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