Problems with generation stamp upgrade
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Key: HADOOP-3677
URL: https://issues.apache.org/jira/browse/HADOOP-3677
Project: Hadoop Core
Issue Type: Bug
Components: dfs
Affects Versions: 0.18.0
Reporter: Konstantin Shvachko
Fix For: 0.18.0
# The generation stamp upgrade renames blocks' meta-files so that the name
contains the block generation stamp as stated in HADOOP-2656.
If a data-node has blocks that do not belong to any files and the name-node
asks the data-node to remove those blocks
during or before the upgrade started the data-node will remove the blocks but
not the meta-files because their names
are still in the old format which is not recognized by the new code. So we can
end up with a number of garbage files which
will be hard to recognize that they are unused and the system will never remove
them automatically.
I think this should be handled by the upgrade code in the end, but may be it
will be right to fix HADOOP-3002 for the 0.18 release,
which will avoid scheduling block removal when the name-node is in safe-mode.
# I was not able to get the upgrade -force option to work. This option lets the
name-node proceed with a distributed upgrade even if
the data-nodes are not able to complete their local upgrades. Did we test this
feature at all for the generation stamp upgrade?
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