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Kihwal Lee commented on HDFS-5526: ---------------------------------- Well, it is being called for {{DataStorage}} when {{recoverTransitionRead()}} is called for the first block pool that is being initialized. {{DataStorage.doUpgrade()}} will simply write the new version and return. So "previous" won't be created. In {{DataStorage.doRollback()}}, the comment says, "Do nothing, if previous directory does not exist" and that's what it does. > Datanode cannot roll back to previous layout version > ---------------------------------------------------- > > Key: HDFS-5526 > URL: https://issues.apache.org/jira/browse/HDFS-5526 > Project: Hadoop HDFS > Issue Type: Bug > Components: datanode > Reporter: Tsz Wo (Nicholas), SZE > Priority: Blocker > > Current trunk layout version is -48. > Hadoop v2.2.0 layout version is -47. > If a cluster is upgraded from v2.2.0 (-47) to trunk (-48), the datanodes > cannot start with -rollback. It will fail with IncorrectVersionException. -- This message was sent by Atlassian JIRA (v6.1#6144)