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https://issues.apache.org/jira/browse/HDFS-7369?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Zhe Zhang updated HDFS-7369:
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Attachment: HDFS-7396-000.patch
A very simple patch for step 1 in the JIRA description. Ultimately we want to
accurately assess the _risk level_ of a block group when some of its EC blocks
are lost. This patch is the first order approximation:
# A block group with _m_ data blocks and _k_ parity blocks is equivalent to a
contiguous block with replication factor _k+1_, because both can tolerate _k_
failures
# If _n_ blocks are healthy among the _m+k_ blocks, it's equivalent to having
_n-m+1_ healthy replicas, calculated from _(k+1) - ((m+k) - n)_, or
_replicationFactor - numLostReplicas_.
> Erasure coding: distribute block recovery work to DataNode
> ----------------------------------------------------------
>
> Key: HDFS-7369
> URL: https://issues.apache.org/jira/browse/HDFS-7369
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Zhe Zhang
> Assignee: Zhe Zhang
> Attachments: HDFS-7396-000.patch
>
>
> This JIRA updates NameNode to handle background / offline recovery of erasure
> coded blocks. It includes 2 parts:
> # Extend {{UnderReplicatedBlocks}} to recognize EC blocks and insert them to
> appropriate priority levels.
> # Update {{ReplicationMonitor}} to distinguish block codec tasks and send a
> new DataNode command.
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