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Gera Shegalov commented on HDFS-6452: ------------------------------------- Hi Aaron, the net improvement should be in the overhead smoothness over time. E.g., we will smooth the storm of {{StandbyException: Operation category READ is not supported in state standby}} [~jingzhao], this is targeted for deployments with automatic failover where the emphasis is on not trying to watch what NN is active all the time. > ConfiguredFailoverProxyProvider should randomize currentProxyIndex on > initialization > ------------------------------------------------------------------------------------ > > Key: HDFS-6452 > URL: https://issues.apache.org/jira/browse/HDFS-6452 > Project: Hadoop HDFS > Issue Type: Improvement > Components: ha, hdfs-client > Affects Versions: 2.4.0 > Reporter: Gera Shegalov > Assignee: Gera Shegalov > > We observe that the clients iterate proxies in the fixed order. Depending on > the order of namenodes in dfs.ha.namenodes.<nameservice> (e.g. 'nn1,nn2') and > the current standby (nn1), all the clients will hit nn1 first, and then > failover to nn2. Chatting with [~lohit] we think we can simply select the > initial value of {{currentProxyIndex}} randomly, and keep the logic of > {{performFailover}} of iterating from left-to-right. This should halve the > unnecessary load on standby NN. -- This message was sent by Atlassian JIRA (v6.2#6252)