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https://issues.apache.org/jira/browse/HDFS-6686?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14071430#comment-14071430
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Tsz Wo Nicholas Sze commented on HDFS-6686:
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Vinay,
# Good catch. We should pass excludedNodes.
# For getAdditionalDatanode(), since the write is already started, there are
already some data in the block. So using replication fallback is correct.
Creation fallback usually is a subset of replication fallback since if there
are not enough storages available, we may fails creation. However, if we fail
replication, it may result in data loss.
Arpit,
# Good catch. We need to pass newBlock as a parameter.
# numOfResults indeed is the number of existing replicas (numOfResults is used
to determine whether local host/local rack/remote rack should be chosen from).
numOfReplicas (call it n) is the number of replicas to be chosen. In our case,
we try to select n storage types but we may only able to get m < n, where m =
storageTypes.size(). So we should update numOfReplicas.
Thanks both of you for the careful reviews!
> Archival Storage: Use fallback storage types
> --------------------------------------------
>
> Key: HDFS-6686
> URL: https://issues.apache.org/jira/browse/HDFS-6686
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Components: namenode
> Reporter: Tsz Wo Nicholas Sze
> Assignee: Tsz Wo Nicholas Sze
> Attachments: h6686_20140721.patch, h6686_20140721c.patch
>
>
> HDFS-6671 changes replication monitor to use block storage policy for
> replication. It should also use the fallback storage types when a particular
> type of storage is full.
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