Uneven Cassandra load

Question

Should a three node Cassandra cluster with a replication factor of 3 have the same load value for all three nodes?

We are using a random partitioner and NetworkTopologyStrategy. Nodetool ring shows equal values for "Owns" but unequal values for "Load".

Load            Owns    Token                                       
                        113427455640312821154458202477256070484     
16.53 GB        33.33%  0                                           
14.8 GB         33.33%  56713727820156410577229101238628035242      
15.65 GB        33.33%  113427455640312821154458202477256070484

Running nodetool repair and cleanup on each node brought the load a little closer but it still seems quite unbalanced.

Is this considered normal?

One node is at exactly 33.3% load. The other two are off from perfect by like 2%. Your expectations are unreasonable. — David Schwartz, Jan 14 '13 at 14:39

score 2 · Answer 1 · answered Oct 26 '13 at 21:10

The Own % communicates which nodes own which part of the Keyspace. However, if the original data is not exactly equal in size or equal in occurrence of the key, then that will be reflected in the data size totals for each nodes as well. This is likely what you are seeing.

score 1 · Answer 2 · answered Apr 29 '15 at 03:22

1

It is completely normal. If the first server has records with more data in it, the load can of course be bigger.

The load on bigger cluster can also be not so evenly distributed (like 49%, 52%, etc).

answered Apr 29 '15 at 03:22

Popinou

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Uneven Cassandra load

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