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https://issues.apache.org/jira/browse/HDFS-7663?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14910002#comment-14910002
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Walter Su commented on HDFS-7663:
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bq. Lease/Block recovery is actually a different topic and is a tricky problem.
As you suggested in HDFS-9040, we can create a separate jira for it..
They have strong relationship when appending is to append a paritial block.
bq. Looks like till now we do not have a correct solution for EC file lease
recovery (at least the protocol for DataNodes to do the recovery work)?
Sorry, we are not going to use {{BlockRecoveryCommand}}?
bq. 3. Appending to a partial block group is actually very similar to "keep
writing after calling hsync/hflush", since we need to overwrite the parity data
of the last stripe. We have an initial proposal in the latest design doc in
HDFS-7285 about this part.
I didn't know client can overwrite/truncate replica on DN. Can you tell me how
to do it? If so, I think appending to a partial block group is a good option.
> Erasure Coding: lease recovery / append on striped file
> -------------------------------------------------------
>
> Key: HDFS-7663
> URL: https://issues.apache.org/jira/browse/HDFS-7663
> Project: Hadoop HDFS
> Issue Type: Sub-task
> Reporter: Jing Zhao
> Assignee: Walter Su
> Attachments: HDFS-7663.00.txt
>
>
> Append should be easy if we have variable length block support from
> HDFS-3689, i.e., the new data will be appended to a new block. We need to
> revisit whether and how to support appending data to the original last block.
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