[
https://issues.apache.org/jira/browse/HDFS-10714?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15404103#comment-15404103
]
Kihwal Lee commented on HDFS-10714:
-----------------------------------
Guessing who is faulty is complicated. Whatever works for a case can break
other cases. It is not safe to remove the last guy, since it might be the only
one that has valid data up to the ACKed bytes in certain cases. May be we
should have the client examine datanodes individually before recreating a
pipeline.
- Have each datanode perform checksum validation up to the ACKed bytes (needs
to be bytes-per-checksum aligned).
- For identifying a bad node, directly write to N nodes for some number of
packets. Exclude failed nodes and rebuild a pipeline.
> Issue in handling checksum errors in write pipeline when fault DN is
> LAST_IN_PIPELINE
> -------------------------------------------------------------------------------------
>
> Key: HDFS-10714
> URL: https://issues.apache.org/jira/browse/HDFS-10714
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Brahma Reddy Battula
> Assignee: Brahma Reddy Battula
>
> We had come across one issue, where write is failed even 7 DN’s are available
> due to network fault at one datanode which is LAST_IN_PIPELINE. It will be
> similar to HDFS-6937 .
> Scenario : (DN3 has N/W Fault and Min repl=2).
> Write pipeline:
> DN1->DN2->DN3 => DN3 Gives ERROR_CHECKSUM ack. And so DN2 marked as bad
> DN1->DN4-> DN3 => DN3 Gives ERROR_CHECKSUM ack. And so DN4 is marked as bad
> ….
> And so on ( all the times DN3 is LAST_IN_PIPELINE) ... Continued till no more
> datanodes to construct the pipeline.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
---------------------------------------------------------------------
To unsubscribe, e-mail: hdfs-issues-unsubscr...@hadoop.apache.org
For additional commands, e-mail: hdfs-issues-h...@hadoop.apache.org
