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From vck <veesee...@gmail.com>
Subject Vnodes and replication
Date Tue, 08 Apr 2014 08:29:56 GMT
After reading through the vnodes and partitioning described in the datastax
documentation, I am still confused about how rows are
partitioned/replicated.

With vnodes, I know that each Node on the ring now supports many token
ranges per Node. However I am still not very clear on how the replication
is carried out.

If I have 4 Nodes A, B, C, D and their ranges are below.

A - [1,2,3,4]
B - [5,6,7,8]
C - [9,10,11,12]
D - [13,14,15,16]

After a shuffle, lets assume the Nodes are shuffled like this.

A - [1,5,13,9]
B - [2,6,14,10]
C - [3,7,15,11]
D - [4,8,16,12]

now if I use a simple replication strategy and RF=3, the first replica
rowkey gets placed on node determined by the partitioner.

Prior to vnode, if my rowkey hash is 2, it gets placed on Nodes A, B, C.
With the above vnode setup, if my rowkey hash is 2, does it get placed in
B, C, D ?

cheers!

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