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https://issues.apache.org/jira/browse/CASSANDRA-12777?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15583301#comment-15583301
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Dikang Gu edited comment on CASSANDRA-12777 at 10/18/16 5:28 PM:
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Sure, I add the limit of the range of take over ratio, for both MIN and MAX
ratios. Here is the updated patch, and the simulation results are here,
https://gist.github.com/DikangGu/29a6b5ab876ff6979de45118b855622b. I'd like to
go with 0.90, since it produces better results.
Thanks.
was (Author: dikanggu):
Sure, I add the limit of the range of take over ratio, for both MIN and MAX
ratios. Here is the updated patch,
https://github.com/DikangGu/cassandra/commit/5e837747974b5faa9833dc55ac5bd33a8c5e8b31,
and the simulation results are here,
https://gist.github.com/DikangGu/29a6b5ab876ff6979de45118b855622b. I'd like to
go with 0.90, since it produces better results.
Thanks.
> Optimize the vnode allocation for single replica per DC
> -------------------------------------------------------
>
> Key: CASSANDRA-12777
> URL: https://issues.apache.org/jira/browse/CASSANDRA-12777
> Project: Cassandra
> Issue Type: Improvement
> Reporter: Dikang Gu
> Assignee: Dikang Gu
> Fix For: 3.x
>
>
> The new vnode allocation algorithm introduced in CASSANDRA-7032 is optimized
> for the situation that there are multiple replicas per DC.
> In our production environment, most cluster only has one replica, in this
> case, the algorithm does not work perfectly. It always tries to split token
> ranges by half, so that the ownership of "min" node could go as low as ~60%
> compared to avg.
> So for single replica case, I'm working on a new algorithm, which is based on
> Branimir's previous commit, to split token ranges by "some" percentage,
> instead of always by half. In this way, we can get a very small variation of
> the ownership among different nodes.
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