question Error: flush failed for required journal in Support Questions

question Error: flush failed for required journal in Support Questions https://community.cloudera.com/t5/Support-Questions/Error-flush-failed-for-required-journal/m-p/52719#M28498 Hi Communnity, Our Development VM CDH 5.9 is HDFS HA enabled. Since there are only five nodes so two JournalNodes are running same with NN but another one is on a DataNode. However, last night, we ran into this below issue and took down both NNs. FATAL org.apache.hadoop.hdfs.server.namenode.FSEditLog: Error: flush failed for required journal (JournalAndStream(mgr=QJM to [xxx.xx.xx.xx:8485, xxx.xx.xx.xx:8485, xxx.xx.xx.xx:8485], stream=QuorumOutputStream starting at txid 9861544)) Sine this is a Dev cluster so no one was using it runing weekend or nights. After extensive search, the potential issue could be NN Garbarge collection pause. Is there a good approach how to debug and tweak the heap setting? Currently, NN heap setting is 4GB on both. Default time out is 20 seconds (dfs.qjournal.select-input-streams.timeout.ms). Any help really appreciated that. Thanks,Silaphet    Mon, 27 Mar 2017 21:06:31 GMT silaphetmounkhaty-3293181 2017-03-27T21:06:31Z