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https://issues.apache.org/jira/browse/HBASE-2312?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Phabricator updated HBASE-2312:
-------------------------------

    Attachment: D99.3.patch

nspiegelberg updated the revision "HBASE-2312 [jira] Possible data loss when RS 
goes into GC pause while rolling HLog".
Reviewers: JIRA, stack

  Minor touchups + reinsert @Ignore since 0.20.205 doesn't have the critical 
patches necessary.  205.1 should however

REVISION DETAIL
  https://reviews.facebook.net/D99

AFFECTED FILES
  src/main/java/org/apache/hadoop/hbase/master/MasterFileSystem.java
  
src/main/java/org/apache/hadoop/hbase/master/handler/ServerShutdownHandler.java
  src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLog.java
  src/main/java/org/apache/hadoop/hbase/regionserver/wal/HLogSplitter.java
  
src/main/java/org/apache/hadoop/hbase/regionserver/wal/SequenceFileLogWriter.java
  
src/main/java/org/apache/hadoop/hbase/replication/regionserver/ReplicationSource.java
  src/test/java/org/apache/hadoop/hbase/regionserver/wal/TestHLogSplit.java

                
> Possible data loss when RS goes into GC pause while rolling HLog
> ----------------------------------------------------------------
>
>                 Key: HBASE-2312
>                 URL: https://issues.apache.org/jira/browse/HBASE-2312
>             Project: HBase
>          Issue Type: Bug
>          Components: master, regionserver
>    Affects Versions: 0.90.0
>            Reporter: Karthik Ranganathan
>            Assignee: Nicolas Spiegelberg
>            Priority: Critical
>             Fix For: 0.92.0
>
>         Attachments: D99.1.patch, D99.2.patch, D99.3.patch
>
>
> There is a very corner case when bad things could happen(ie data loss):
> 1)    RS #1 is going to roll its HLog - not yet created the new one, old one 
> will get no more writes
> 2)    RS #1 enters GC Pause of Death
> 3)    Master lists HLog files of RS#1 that is has to split as RS#1 is dead, 
> starts splitting
> 4)    RS #1 wakes up, created the new HLog (previous one was rolled) and 
> appends an edit - which is lost
> The following seems like a possible solution:
> 1)    Master detects RS#1 is dead
> 2)    The master renames the /hbase/.logs/<regionserver name>  directory to 
> something else (say /hbase/.logs/<regionserver name>-dead)
> 3)    Add mkdir support (as opposed to mkdirs) to HDFS - so that a file 
> create fails if the directory doesn't exist. Dhruba tells me this is very 
> doable.
> 4)    RS#1 comes back up and is not able create the new hlog. It restarts 
> itself.

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