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https://issues.apache.org/jira/browse/HBASE-13832?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14601868#comment-14601868
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Matteo Bertozzi commented on HBASE-13832:
-----------------------------------------
even with the patch the master will not start until the 3rd data node is back.
in theory you should ping pong between the backup masters until something a DN
is available.
what the patch does is just retry for some time hoping that a 3rd data node is
online, before giving up.
> Procedure V2: master fail to start due to WALProcedureStore sync failures
> when HDFS data nodes count is low
> -----------------------------------------------------------------------------------------------------------
>
> Key: HBASE-13832
> URL: https://issues.apache.org/jira/browse/HBASE-13832
> Project: HBase
> Issue Type: Sub-task
> Components: master, proc-v2
> Affects Versions: 2.0.0, 1.1.0, 1.2.0
> Reporter: Stephen Yuan Jiang
> Assignee: Matteo Bertozzi
> Priority: Critical
> Fix For: 2.0.0, 1.1.2, 1.3.0, 1.2.1
>
> Attachments: HBASE-13832-v0.patch, HDFSPipeline.java
>
>
> when the data node < 3, we got failure in WALProcedureStore#syncLoop() during
> master start. The failure prevents master to get started.
> {noformat}
> 2015-05-29 13:27:16,625 ERROR [WALProcedureStoreSyncThread]
> wal.WALProcedureStore: Sync slot failed, abort.
> java.io.IOException: Failed to replace a bad datanode on the existing
> pipeline due to no more good datanodes being available to try. (Nodes:
> current=[DatanodeInfoWithStorage[10.333.444.555:50010,DS-3c7777ed-93f4-47b6-9c23-1426f7a6acdc,DISK],
>
> DatanodeInfoWithStorage[10.222.666.777:50010,DS-f9c983b4-1f10-4d5e-8983-490ece56c772,DISK]],
>
> original=[DatanodeInfoWithStorage[10.333.444.555:50010,DS-3c7777ed-93f4-47b6-9c23-1426f7a6acdc,DISK],
> DatanodeInfoWithStorage[10.222.666.777:50010,DS-f9c983b4-1f10-4d5e-8983-
> 490ece56c772,DISK]]). The current failed datanode replacement policy is
> DEFAULT, and a client may configure this via
> 'dfs.client.block.write.replace-datanode-on-failure.policy' in its
> configuration.
> at
> org.apache.hadoop.hdfs.DFSOutputStream$DataStreamer.findNewDatanode(DFSOutputStream.java:951)
> {noformat}
> One proposal is to implement some similar logic as FSHLog: if IOException is
> thrown during syncLoop in WALProcedureStore#start(), instead of immediate
> abort, we could try to roll the log and see whether this resolve the issue;
> if the new log cannot be created or more exception from rolling the log, we
> then abort.
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