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Type:
New Feature
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Status: Resolved
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Priority:
Major
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Resolution: Fixed
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Affects Version/s: None
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Component/s: balancer & mover, namenode
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Labels:None
The performance of Active NameNode could be impact when Balancer requests #getBlocks, since query blocks of overly full DNs performance is extremely inefficient currently. The main reason is NameNodeRpcServer#getBlocks hold read lock for long time. In extreme case, all handlers of Active NameNode RPC server are occupied by one reader NameNodeRpcServer#getBlocks and other write operation calls, thus Active NameNode enter a state of false death for number of seconds even for minutes.
The similar performance concerns of Balancer have reported by HDFS-9412, HDFS-7967, etc.
If Standby NameNode can shoulder #getBlocks heavy burden, it could speed up the progress of balancing and reduce performance impact to Active NameNode.
- blocks
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HDFS-15368 TestBalancerWithHANameNodes#testBalancerWithObserver failed occasionally
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- Resolved
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- is blocked by
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HDFS-12976 Introduce ObserverReadProxyProvider
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- Resolved
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- relates to
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HDFS-14162 Balancer should work with ObserverNode
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- Resolved
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