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https://issues.apache.org/jira/browse/HDFS-10178?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kihwal Lee updated HDFS-10178:
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Attachment: HDFS-10178.patch
The following is from {{BlockSender}}, added by HDFS-6934.
{code:java}
// The meta file will contain only the header if the NULL checksum
// type was used, or if the replica was written to transient storage.
// Checksum verification is not performed for replicas on transient
// storage. The header is important for determining the checksum
// type later when lazy persistence copies the block to non-transient
// storage and computes the checksum.
if (metaIn.getLength() > BlockMetadataHeader.getHeaderSize()) {
{code}
The code in the {{BlockSender}} makes a wrong assumption. If I simply changes
{{>}} to {{>=}}, my test passes, but some of the lazy persist test cases fail.
So I added another argument to the constructor.
[~cnauroth], can you take a look at my patch? I am not familiar with the lazy
persist feature. There might be a better way.
> Permanent write failures can happen if pipeline recoveries occur for the
> first packet
> -------------------------------------------------------------------------------------
>
> Key: HDFS-10178
> URL: https://issues.apache.org/jira/browse/HDFS-10178
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Kihwal Lee
> Assignee: Kihwal Lee
> Priority: Critical
> Attachments: HDFS-10178.patch
>
>
> We have observed that write fails permanently if the first packet doesn't go
> through properly and pipeline recovery happens. If the packet header is sent
> out, but the data portion of the packet does not reach one or more datanodes
> in time, the pipeline recovery will be done against the 0-byte partial block.
>
> If additional datanodes are added, the block is transferred to the new nodes.
> After the transfer, each node will have a meta file containing the header
> and 0-length data block file. The pipeline recovery seems to work correctly
> up to this point, but write fails when actual data packet is resent.
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