He Tianyi created HDFS-9665:
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Summary: Cilents are easily affected by standby namenode
Key: HDFS-9665
URL: https://issues.apache.org/jira/browse/HDFS-9665
Project: Hadoop HDFS
Issue Type: Wish
Components: hdfs-client, namenode
Affects Versions: 2.6.0
Reporter: He Tianyi
Assignee: He Tianyi
Priority: Minor
My case is during restarting of standby NameNode, there is chances that
{{hadoop fs}} command get hung until either IPC timeout reached or
{{StandbyException}} received, and then failover to active NameNode.
Normally, duration of the 'hung stage' depends on {{min(timeout_configuration,
rpc_queue_time)}}. However, RPC queue in standby NameNode is usually filled
with block reports at this period, client requests can't get processed quickly.
I wish to get rid of this, by one of the following manners:
a) we distinguish priority in RPC queue (chances causing starvation)
b) we speculate first request, send it to both NameNodes, and take one valid
response.
c) make client aware of HA state (by accessing ZK probably, chances causing
performance issue)
Any suggestions or comments?
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