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Suresh Srinivas commented on HDFS-7231: --------------------------------------- Allen, I just rewrote the steps with additional details to clarify: # Upgrade 2.0.5 cluster to 2.2 # Do not -finalizeUpgrade # Install 2.4.1 binaries on the cluster machines. Start the datanodes on 2.4.1. # Start namenode -upgrade option. # Namenode start fails because 2.0.5 to 2.2 upgrade is still in progress # Leave 2.4.1 DNs running # Install binaries on NN to 2.2 # Start NN on 2.2 with no upgrade related options So far things are clear. Then you go on to say, the following: bq. DNs now do a partial roll-forward, rendering them unable to continue What do you mean by this? bq. admins manually repair version files on those broken directories This is as you know is a recipe for disaster. Let me ask you a question. Before you go on to 2.4.1, if you do finalize of upgrade what happens? > rollingupgrade needs some guard rails > ------------------------------------- > > Key: HDFS-7231 > URL: https://issues.apache.org/jira/browse/HDFS-7231 > Project: Hadoop HDFS > Issue Type: Bug > Affects Versions: 2.6.0 > Reporter: Allen Wittenauer > Priority: Blocker > > See first comment. -- This message was sent by Atlassian JIRA (v6.3.4#6332)