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https://issues.apache.org/jira/browse/HDFS-6353?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13999176#comment-13999176
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Kihwal Lee commented on HDFS-6353:
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We run a monitoring tool that watches the name.dir for fsimages. If new one
does not appear in configured_checkpoint_interval * factor, it alerts
operators. We could at least show it on the namenode UI. If we expose the
last checkpoint time, interval (time & # tx) and txid in jmx, javascript can
take care of the rest.
> Handle checkpoint failure more gracefully
> -----------------------------------------
>
> Key: HDFS-6353
> URL: https://issues.apache.org/jira/browse/HDFS-6353
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Suresh Srinivas
> Assignee: Jing Zhao
>
> One of the failure patterns I have seen is, in some rare circumstances, due
> to some inconsistency the secondary or standby fails to consume editlog. The
> only solution when this happens is to save the namespace at the current
> active namenode. But sometimes when this happens, unsuspecting admin might
> end up restarting the namenode, requiring more complicated solution to the
> problem (such as ignore editlog record that cannot be consumed etc.).
> How about adding the following functionality:
> When checkpointer (standby or secondary) fails to consume editlog, based on a
> configurable flag (on/off) to let the active namenode know about this
> failure. Active namenode can enters safemode and saves namespace. When in
> this type of safemode, namenode UI also shows information about checkpoint
> failure and that it is saving namespace. Once the namespace is saved,
> namenode can come out of safemode.
> This means service unavailability (even in HA cluster). But it might be worth
> it to avoid long startup times or need for other manual fixes. Thoughts?
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