Details
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Improvement
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Status: Open
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Major
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Resolution: Unresolved
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2.6.0
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None
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2 namenodes HA, 6 datanodes in two racks
Description
Each file has a setting of 3 replicas. split on different racks.
After a simulated crash of one rack (shutdown of all nodes, deleted data-directory an started nodes) and decommssion of one of the nodes in the orther rack the replication does not follow 'normal' rules...
My cluster has appx 25 mill files, and the one node I now try to decommision has 9 millions underreplicated blocks, and 3,5 million blocks with 'no live replicas'. After a restart of the node, it starts to replicate both types of blocks, but after a while, it only repliates under-replicated blocks with other live copies. I would think that the 'normal' way to do this would be to make sure that all blocks this node keeps the only copy of, should be the first to be replicated/balanced ?