Arpit Agarwal created HDFS-6981:
-----------------------------------
Summary: DN upgrade with layout version change should not use trash
Key: HDFS-6981
URL: https://issues.apache.org/jira/browse/HDFS-6981
Project: Hadoop HDFS
Issue Type: Bug
Components: datanode
Affects Versions: 3.0.0
Reporter: James Thomas
Post HDFS-6800, we can encounter the following scenario:
# We start with DN software version -55 and initiate a rolling upgrade to
version -56
# We delete some blocks, and they are moved to trash
# We roll back to DN software version -55 using the -rollback flag – since we
are running the old code (prior to this patch), we will restore the previous
directory but will not delete the trash
# We append to some of the blocks that were deleted in step 2
# We then restart a DN that contains blocks that were appended to – since the
trash still exists, it will be restored at this point, the appended-to blocks
will be overwritten, and we will lose the appended data
So I think we need to avoid writing anything to the trash directory if we have
a previous directory.
Thanks to [~james.thomas] for reporting this.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
