Add a test to monitor the distribution of vnode to physical node #18147
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alluxio-bot, merge this please |
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merge failed: |
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alluxio-bot, merge this please |
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What changes are proposed in this pull request?
Add a test so we can monitor the vnode distribution is not too uneven.
This test calculates the standard deviation over mean on the collection of virtual nodes assigned to physical nodes. It arbitrarily bounds it at 0.25, but ideally this number should get smaller over time as we improve hashing algorithm
and use better ways to assign virtual nodes to physical nodes.
Why are the changes needed?
We may change hashing algorithm and virtual node assignment in the future, this will provide guidance and catch errors.
Does this PR introduce any user facing changes?
No.