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HBase, mail # user - HBase and Cassandra on StackOverflow


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Re: HBase and Cassandra on StackOverflow
Gary Helmling 2011-08-31, 18:21
> Since this is fairly off-topic at this point, I'll keep it short. The
> simple
> rule for Dynamo goes like this: if (R+W>N && W>=Quorum), then you're
> guaranteed a consistent result always. You get eventual consistency if
> W>=Quorum. If W<Quorum, then you can get inconsistent data that must be
> detected/fixed by readers (often using timestamps or similar techniques).
> Joe is right, enforcing (W=3, R=1, N=3) on a Dynamo system gives the same
> (provably identical?) behaviour as HBase, with respect to consistency.
>
>
For those interested in a comparison of the consistency behavior, there's an
older, but really excellent thread on quora with detailed analysis:
http://www.quora.com/How-does-HBase-write-performance-differ-from-write-performance-in-Cassandra-with-consistency-level-ALL

Don't miss the last answer in the the thread.  It's unfortunately collapsed
due to some quora policy, but it contains some of the best details.