Hi @dmitrybalak . Try the below Cloudera article and see if that helps resolve this.   https://my.cloudera.com/knowledge/Rebalance-option-is-greyed-out-in-the-Cloudera-Manager-under?id=91268 ... View more

Hi, @yagoaparecidoti With a replication factor of 3, the BlockPlacementPolicyDefault will put one replica on the local machine if the writer is on a datanode, otherwise on a random datanode in the same rack as that of the writer, another replica on a node in a different (remote) rack, and the last on a different node in the same remote rack. So totally 2 racks will be used, in sceneraio like 2 racks going down at the same time will cause data inavailability where using BlockPlacementPolicyRackFaultTolerant will help in placing 3 blocks on 3 different racks.   So, you can safely set 2 racks. In case, you want to go with BlockPlacementPolicyRackFaultTolerant ( rare cases where both the racks go down ), you can follow the below doc :   https://hadoop.apache.org/docs/stable/hadoop-project-dist/hadoop-hdfs/HdfsBlockPlacementPolicies.html ... View more

Hi @damon Apart from these CancelledKeyException, are you seeing any other specific warnings or errors in the Zookeeper logs? ... View more

Hi @hanumanth There could be various factors that could cause such issues.    Can you check what the Namenode was logging at the same time?  It could be some Block Placement issue as the Datanodes are considered for the operation but something has restricted the write/read. ... View more

Hi, @tangxu Do check if the below Cloudera article helps you.   https://community.cloudera.com/t5/Customer/Configure-SPNEGO-Kerberos-Authentication-from-Windows/ta-p/89450   https://community.cloudera.com/t5/Customer/Authentication-Fails-Configuring-SPNEGO-Kerberos/ta-p/72030     ... View more