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https://issues.apache.org/jira/browse/HDFS-9665?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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He Tianyi resolved HDFS-9665.
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    Resolution: Duplicate

> 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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