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https://issues.apache.org/jira/browse/FLUME-1516?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hari Shreedharan updated FLUME-1516:
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    Attachment:     (was: FLUME-1516.patch)
    
> Write Dual Checkpoints to avoid replays
> ---------------------------------------
>
>                 Key: FLUME-1516
>                 URL: https://issues.apache.org/jira/browse/FLUME-1516
>             Project: Flume
>          Issue Type: New Feature
>          Components: Channel
>    Affects Versions: v1.3.0
>            Reporter: Brock Noland
>            Assignee: Hari Shreedharan
>             Fix For: v1.4.0
>
>         Attachments: DualCheckpoints.pdf
>
>
> Per the LFS paper (http://www.cs.berkeley.edu/~brewer/cs262/LFS.pdf) we can 
> write two checkpoints to avoid replaying the logs in the case we 
> crash/shutdown while writing a checkpoint.
> Section 4:
> "In order to handle a crash during a checkpoint operation there are actually 
> two checkpoint regions, and checkpoint operations alternate between them. The 
> checkpoint time is in the last block of the checkpoint so if the checkpoint 
> fails the time will not be updated. During reboot, the system reads both 
> checkpoint regions and uses the one with the most recent time."

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