@samarsimha  Oh well and good, are you downloading Nifi 1.10.0 from https://nifi.apache.org/download.html  released just last week November 4th, 2019  according to the documentation you  MUST upgrade to zookeeper version 3.5.5  which is the recommended version. I am sure if you align  zookeeper version to the documentation.   Task 6624 is automatic but the 6578 must be done manually  [NIFI-6624] - Automatically migrate old embedded zookeeper.properties files to the new format [NIFI-6578] - Upgrade zookeeper to 3.5.5   Hope that helps     ... View more

@mokkan  Yes having multiple copies is good  backup strategy so long as the mount points are physically different disks that don't share disk controllers   Please, can you share feedback on the outcome of the earlier procedure?  I have not tried adding addition FSIMAGE and Edits location after the creation of the cluster  I am  wondering whether you could startup the name node unless you formated it which is now a different story altogether   Happy hadooping ... View more

@mokkan  You are not far from the truth !!! The name NameNode contains the metadata of the HDFS files ie permissions and location etc . This metadata is present in a serialized form inside a single file(fsimage) and edits file that has a log of all the changes made to the file system. The fsimage file is kept both on-disk and in-memory. All changes to file system is reflected in-memory and periodically transferred to disk. Details on how to fetch fsimage and edits file is given here HDFS File System Metadata Backup. If you format the namenode then the basic information about ownership, permissions and location are deleted from namenode directory which is specified in the hdfs-site.xml as dfs.namenode.name.dir the namenode metadata will be gone but your data in the data nodes intact actually formatting a Namenode will not format the Datanode. In the other hand namenode will no longer receieve heartbeats from the datanode nor where your data is as -format assign a new namespace ID to the namenode a *** You will need to change your namespaceID in your datanode to make your datanode work. This will be at /hadoop/hdfs/namenode/current [root@nanyuki current]# cat VERSION #Fri Nov 15 21:29:31 CET 2019 namespaceID=107632589 clusterID=CID-72e79d8b-ea16-4d5c-9920-6b579e5c26b0 cTime=0 storageType=NAME_NODE blockpoolID=BP-2067995211-192.168.0.101-1537740712051 layoutVersion=-63   Once the new namespaceID has been updated on all the datanodes then the namenode will start receiving heartbeats from the datanodes as each datanodes will report during the heartbeat the files it has and eventually that is the information the namenode will use to rebuild its metadata   HTH  ... View more