When the NN is configured with a QJM, we see the following warning message every time a checkpoint is made or uploaded:
12/12/10 16:07:52 WARN namenode.FSEditLog: Unable to determine input streams from QJM to [127.0.0.1:13001, 127.0.0.1:13002, 127.0.0.1:13003]. Skipping.
org.apache.hadoop.hdfs.qjournal.client.QuorumException: Got too many exceptions to achieve quorum size 2/3. 3 exceptions thrown:
127.0.0.1:13002: Asked for firstTxId 114837 which is in the middle of file /tmp/jn-2/myjournal/current/edits_0000000000000095185-0000000000000114846
This is because, since
HDFS-2946, the NN calls selectInputStreams to determine the number of log segments and put a cap on the number. This API throws an exception in the case of QJM if the argument falls in the middle of an edit log boundary.