Vinay created HDFS-5504:
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Summary: In HA mode, OP_DELETE_SNAPSHOT is not decrementing the
safemode threshold, leads to NN safemode.
Key: HDFS-5504
URL: https://issues.apache.org/jira/browse/HDFS-5504
Project: Hadoop HDFS
Issue Type: Bug
Components: snapshots
Reporter: Vinay
Assignee: Vinay
1. HA installation, standby NN is down.
2. delete snapshot is called and it has deleted the blocks from blocksmap and
all datanodes. log sync also happened.
3. before next log roll NN crashed
4. When the namenode restartes then it will fsimage and finalized edits from
shared storage and set the safemode threshold. which includes blocks from
deleted snapshot also. (because this edits is not yet read as namenode is
restarted before the last edits segment is not finalized)
5. When it becomes active, it finalizes the edits and read the delete snapshot
edits_op. but at this time, it was not reducing the safemode count. and it will
continuing in safemode.
6. On next restart, as the edits is already finalized, on startup only it will
read and set the safemode threshold correctly.
But one more restart will bring NN out of safemode.
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