Kihwal Lee created HDFS-10857:
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Summary: Rolling upgrade can make data unavailable when the
cluster has many failed volumes
Key: HDFS-10857
URL: https://issues.apache.org/jira/browse/HDFS-10857
Project: Hadoop HDFS
Issue Type: Bug
Reporter: Kihwal Lee
Priority: Critical
When the marker file or trash dir is created or removed during the heartbeat
response processing, an {{IOException}} is thrown if tried on a failed volume.
This stops processing of the rest of storage directories and any DNA commands
that were part of the heartbeat response.
While this is happening, the block token key update does not happen and all
read and write requests start to fail, until the upgrade is finalized and the
DN receives a new key. All it takes is one failed volume. If there are three
such nodes in the cluster, it is very likely that some blocks cannot be read.
The NN has no idea unlike the common missing blocks scenarios, although the
effect is the same.
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