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From mcasandra <mohitanch...@gmail.com>
Subject Re: Understand eventually consistent
Date Thu, 24 Feb 2011 00:42:55 GMT

I am reading this again http://wiki.apache.org/cassandra/HintedHandoff and
got little confused. This is my understanding about how HH should work based
on what I read in Dynamo Paper:

1) Say node A, B, C, D, E are in the cluster in a ring (in that order). 
2) For a given key K RF=3.
3) Node B holds theyhash of that key K. Which means when K is written it
will be written to B (owner of the hash) + C + D since RF = 3
4) If Node D goes down and there is a write again to key K then this time
key K row will be written with W=1 to B (owner) + C + E (HH) since RF=3
needs to be satisfied. Is this correct?
5) In above scenario where node D is down and if we are reading at W=2 and
R=2 would it fail even though original nodes B + C are up? Here I am
thinking W=2 and R=2 means that 2 nodes that hold the key K are up so it
satisfies the CL and thus writes and read will not fail.
-- 
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