[
https://issues.apache.org/jira/browse/HDFS-5526?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13827256#comment-13827256
]
Vinay commented on HDFS-5526:
-----------------------------
Yes you are right nicholas. We dont have any clue whether we have upgraded or
not. One thing is Version file will be overwritten if the layoutVersion is
latest or ctime is latest., But that namenode also should be part of the same
cluster otherwise upgrade will not happen.
One more thing, ./current/VERSION will be overwritten everytime DN restarted
after upgrade because of the following check.
{code} // do upgrade
if (this.layoutVersion > HdfsConstants.LAYOUT_VERSION
|| this.cTime < nsInfo.getCTime()) {
doUpgrade(sd, nsInfo); // upgrade
return;
}{code}
because, ./current/VERSION file ctime is always same. and upgraded NN will have
higher ctime.
> 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
> Assignee: Kihwal Lee
> Priority: Blocker
> Attachments: HDFS-5526.patch
>
>
> 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)
