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https://issues.apache.org/jira/browse/HDFS-12102?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16111696#comment-16111696
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Nathan Roberts commented on HDFS-12102:
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[~arpitagarwal] Hi Arpit. To provide a bit more background on this feature -
we've seen multiple cases where there are many bad blocks stored on a disk.
Just because of the way drives tend to fail, one bad block indicates there are
probably many others. The volumeScanner will eventually find them over a
multi-week period, but this leaves the cluster susceptible to data-loss due to
lots of replicas being corrupt on a single misbehaving disk. The idea with this
jira is to use a found corrupt block as a hint that there are likely more and
we should do a scan over the drive at a faster rate to more quickly find other
corrupt blocks on the drive. Thoughts?
> VolumeScanner throttle dropped (fast scan enabled) when there is a corrupt
> block
> --------------------------------------------------------------------------------
>
> Key: HDFS-12102
> URL: https://issues.apache.org/jira/browse/HDFS-12102
> Project: Hadoop HDFS
> Issue Type: New Feature
> Components: datanode, hdfs
> Affects Versions: 2.8.2
> Reporter: Ashwin Ramesh
> Priority: Minor
> Fix For: 2.8.2
>
> Attachments: HDFS-12102-001.patch, HDFS-12102-002.patch,
> HDFS-12102-003.patch
>
>
> When the Volume scanner sees a corrupt block, it restarts the scan and scans
> the blocks at much faster rate with a negligible scan period. This is so that
> it doesn't take 3 weeks to report blocks since a corrupt block means
> increased likelihood that there are more corrupt blocks.
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