hadoop-hdfs-issues mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (HDFS-3863) QJM: track last "committed" txid
Date Wed, 29 Aug 2012 18:48:07 GMT

    [ https://issues.apache.org/jira/browse/HDFS-3863?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13444316#comment-13444316
] 

Todd Lipcon commented on HDFS-3863:
-----------------------------------

BTW, I forgot to address this comment:

{quote}However, imagine a stupid administrator replaces JN2 and JN3 with some new machines.
Since JN1 is far behind, it doesn't know about the journal number committed by JN2 and JN3.
It passes the check.
{quote}

In the case that the admin replaces a majority of nodes, then the NN would refuse to start
up because they would throw "JournalNotFormattedException". See the discussion on https://issues.apache.org/jira/browse/HDFS-3743
                
> QJM: track last "committed" txid
> --------------------------------
>
>                 Key: HDFS-3863
>                 URL: https://issues.apache.org/jira/browse/HDFS-3863
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: ha
>    Affects Versions: QuorumJournalManager (HDFS-3077)
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>
> Per some discussion with [~stepinto] [here|https://issues.apache.org/jira/browse/HDFS-3077?focusedCommentId=13422579&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13422579],
we should keep track of the "last committed txid" on each JournalNode. Then during any recovery
operation, we can sanity-check that we aren't asked to truncate a log to an earlier transaction.
> This is also a necessary step if we want to support reading from in-progress segments
in the future (since we should only allow reads up to the commit point)

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira

Mime
View raw message