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https://issues.apache.org/jira/browse/HDFS-9106?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Kihwal Lee updated HDFS-9106:
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Description:
When a new node is added to a write pipeline during flush/sync, if the partial
block transfer fails, the write will fail permanently without retrying or
continuing with whatever is in the pipeline.
The transfer often fails in busy clusters due to timeout. There is no
per-packet ACK between client and datanode or between source and target
datanodes. If the total transfer time exceeds the configured timeout + 10
seconds (2 * 5 seconds slack), it is considered failed. Naturally, the failure
rate is higher with bigger block sizes.
I propose following changes:
- Transfer timeout needs to be different from per-packet timeout.
- transfer should be retried if fails.
was:
When a new node is added to a write pipeline during flush/sync, if the partial
block transfer fails, the write will fail permanently without retrying or
continuing with whatever is in the pipeline.
The transfer often fails in busy clusters due to timeout. There is no
per-packet ACK between client and datanode or between source and target
datanodes. If the total transfer time exceeds the configured timeout + 10
seconds (2 * 5 seconds slack), it is considered failed.
I propose following changes:
- Transfer timeout needs to be different from per-packet timeout.
- transfer should be retried if fails.
> Transfer failure during pipeline recovery causes permanent write failures
> -------------------------------------------------------------------------
>
> Key: HDFS-9106
> URL: https://issues.apache.org/jira/browse/HDFS-9106
> Project: Hadoop HDFS
> Issue Type: Bug
> Reporter: Kihwal Lee
> Priority: Critical
>
> When a new node is added to a write pipeline during flush/sync, if the
> partial block transfer fails, the write will fail permanently without
> retrying or continuing with whatever is in the pipeline.
> The transfer often fails in busy clusters due to timeout. There is no
> per-packet ACK between client and datanode or between source and target
> datanodes. If the total transfer time exceeds the configured timeout + 10
> seconds (2 * 5 seconds slack), it is considered failed. Naturally, the
> failure rate is higher with bigger block sizes.
> I propose following changes:
> - Transfer timeout needs to be different from per-packet timeout.
> - transfer should be retried if fails.
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