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https://issues.apache.org/jira/browse/HDFS-13709?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Chen Zhang updated HDFS-13709:
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Description:
In our online cluster, the BlockPoolSliceScanner is turned off, and sometimes
disk bad track may cause data loss.
For example, there are 3 replicas on 3 machines A/B/C, if a bad track occurs on
A's replica data, and someday B and C crushed at the same time, NN will try to
replicate data from A but failed, this block is corrupt now but no one knows,
because NN think there is at least 1 healthy replica and it keep trying to
replicate it.
When reading a replica which hav data on bad track, OS will return an EIO
error, if DN reports the bad block as soon as it got an EIO, we can find this
case ASAP and try to avoid data loss
> Report bad block to NN when transfer block encounter EIO exception
> ------------------------------------------------------------------
>
> Key: HDFS-13709
> URL: https://issues.apache.org/jira/browse/HDFS-13709
> Project: Hadoop HDFS
> Issue Type: Improvement
> Components: datanode
> Reporter: Chen Zhang
> Assignee: Chen Zhang
> Priority: Major
>
> In our online cluster, the BlockPoolSliceScanner is turned off, and sometimes
> disk bad track may cause data loss.
> For example, there are 3 replicas on 3 machines A/B/C, if a bad track occurs
> on A's replica data, and someday B and C crushed at the same time, NN will
> try to replicate data from A but failed, this block is corrupt now but no one
> knows, because NN think there is at least 1 healthy replica and it keep
> trying to replicate it.
> When reading a replica which hav data on bad track, OS will return an EIO
> error, if DN reports the bad block as soon as it got an EIO, we can find
> this case ASAP and try to avoid data loss
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