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https://issues.apache.org/jira/browse/HADOOP-4995?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12662184#action_12662184
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Raghu Angadi commented on HADOOP-4995:
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Some time back I had a proposal to checksum the fsimage. Here, each record
(about a few hundred bytes) is checksumed rather than the whole file. This
helps both with the verification as well as better recovery from multiple
copies. In case of multiple copies, the image can be recovered as long as both
copies are not damaged at the same location.
> Offline Namenode fsImage verification
> -------------------------------------
>
> Key: HADOOP-4995
> URL: https://issues.apache.org/jira/browse/HADOOP-4995
> Project: Hadoop Core
> Issue Type: New Feature
> Reporter: Brian Bockelman
>
> Currently, there is no way to verify that a copy of the fsImage is not
> corrupt. I propose that we should have an offline tool that loads the
> fsImage into memory to see if it is usable. This will allow us to automate
> backup testing to some extent.
> One can start a namenode process on the fsImage to see if it can be loaded,
> but this is not easy to automate.
> To use HDFS in production, it is greatly desired to have both checkpoints -
> and have some idea that the checkpoints are valid! No one wants to see the
> day where they reload from backup only to find that the fsImage in the backup
> wasn't usable.
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