> http://www.quora.com/How-does-HBase-write-performance-differ-from-write-performance-in-Cassandra-with-consistency-level-ALL
Thanks, that was what I was referring to earlier in this thread. Now bookmarked. Comments there from those more knowledgable about Cassandra than I seem to indicate that N=3,W=3,R=1 is not practical (one commenter I know to be an expert characterizes it as "suicidal"), and the comments in the collapsed answer indicate there are corner cases known to Cassandra experts where HBase-equivalent strong consistency cannot be maintained even with that setting. So it seems that claims that Cassandra can provide consistency equivalent to HBase are erroneous. Best regards, - Andy Problems worthy of attack prove their worth by hitting back. - Piet Hein (via Tom White) >________________________________ >From: Gary Helmling <ghelml...@gmail.com> >To: user@hbase.apache.org >Sent: Thursday, September 1, 2011 2:21 AM >Subject: Re: HBase and Cassandra on StackOverflow > >> 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. > > >
