Hello @Asfahan thank you for the answer, yes, I understand that the cluster it'a little oversized About the topic, I don't find any "Block report queue full" message but several write-lock with long duration but, strange enough, not during hdfs service startup What I find is a number of request coming via NFS Gateway (around 3000/minute) and several GC (Allocation Failure) in gc log in the first 20 minutes of startup and several about a the end when all the datanodes reported thei blocks The NN has 160GB of heap and DN 30GB What I found strange is dfs_datanode_handler_count set to 3, that might be the cause of the original issue that forced me to restart the service In fact, I was decommissioning one node and when I started, suddenly I've experience a huge performance degradation, even if network, hdfs and disk I/O were not so critical (cluster Net I/O peak was 280 MB/s, hdfs I/O 190 MB/s, disk I/O write peak of 300 MB/s)
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