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Date: Sun, 15 Oct 2017 02:48:00 +0000 (UTC)
From: "Xiao Chen (JIRA)" <jira@apache.org>
To: hdfs-issues@hadoop.apache.org
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Subject: [jira] [Commented] (HDFS-12642) Log block and datanode details in
 BlockRecoveryWorker
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archived-at: Sun, 15 Oct 2017 02:48:10 -0000


    [ https://issues.apache.org/jira/browse/HDFS-12642?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16204993#comment-16204993 ] 

Xiao Chen commented on HDFS-12642:
----------------------------------

Thanks Yongjun for the review.

Patch 2 addressed the comments. New example logs for convenience:
{noformat}
2017-10-14 19:43:25,345 [org.apache.hadoop.hdfs.server.datanode.BlockRecoveryWorker$1@40bdcea2] 
INFO  datanode.DataNode (BlockRecoveryWorker.java:logRecoverBlock(549)) - 
BlockRecoveryWorker: NameNode at localhost/127.0.0.1:52885 calls recoverBlock(BP-342842897-10.0.0.51-1508035399504:blk_1073741827_1003,
targets=[DatanodeInfoWithStorage[127.0.0.1:52896,null,null], DatanodeInfoWithStorage[127.0.0.1:52901,null,null], DatanodeInfoWithStorage[127.0.0.1:52888,null,null]],
newGenerationStamp=1004, newBlock=null, isStriped=false)

2017-10-14 19:43:25,368 [org.apache.hadoop.hdfs.server.datanode.BlockRecoveryWorker$1@40bdcea2] INFO  datanode.DataNode (BlockRecoveryWorker.java:syncBlock(200)) - 
BlockRecoveryWorker: block=BP-342842897-10.0.0.51-1508035399504:blk_1073741827_1003 (length=952), isTruncateRecovery=false, 
syncList=[block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52896,null,null], 
block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52901,null,null], 
block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52888,null,null]]

2017-10-14 19:43:25,369 [org.apache.hadoop.hdfs.server.datanode.BlockRecoveryWorker$1@40bdcea2] INFO  datanode.DataNode (BlockRecoveryWorker.java:syncBlock(291)) - 
BlockRecoveryWorker: block=BP-342842897-10.0.0.51-1508035399504:blk_1073741827_1003 (length=952),
bestState=FINALIZED, newBlock=BP-342842897-10.0.0.51-1508035399504:blk_1073741827_1004 (length=952), 
participatingList=[block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52896,null,null], 
block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52901,null,null], 
block:blk_1073741827_1003[numBytes=952,originalReplicaState=FINALIZED] node:DatanodeInfoWithStorage[127.0.0.1:52888,null,null]]
{noformat}

> Log block and datanode details in BlockRecoveryWorker
> -----------------------------------------------------
>
>                 Key: HDFS-12642
>                 URL: https://issues.apache.org/jira/browse/HDFS-12642
>             Project: Hadoop HDFS
>          Issue Type: Improvement
>          Components: datanode
>            Reporter: Xiao Chen
>            Assignee: Xiao Chen
>         Attachments: HDFS-12642.01.patch
>
>
> In a recent investigation, we have seen a weird block recovery issue, which is difficult to reach to a conclusion because of insufficient logs.
> For the most critical part of the events, we see block recovery failed to {{commitBlockSynchronization]} on the NN, due to the block not closed. This leaves the file as open forever (for 1+ months).
> The reason the block was not closed on NN, was because it is configured with {{dfs.namenode.replication.min}} =2, and only 1 replica was with the latest genstamp.
> We were not able to tell why only 1 replica is on latest genstamp.
> From the primary node of the recovery (ps2204), {{initReplicaRecoveryImpl}} was called on each of the 7 DNs the block were ever placed. All DNs but ps2204 and ps3765 failed because of genstamp comparison - that's expected. ps2204 and ps3765 have gone past the comparison (since no exceptions from their logs), but {{updateReplicaUnderRecovery}} only appeared to be called on ps3765.
> This jira is to propose we log more details when {{BlockRecoveryWorker}} is about to call {{updateReplicaUnderRecovery}} on the DataNodes, so this could be figured out in the future.
> {noformat}
> $ grep "updateReplica:" ps2204.dn.log 
> $ grep "updateReplica:" ps3765.dn.log 
> hadoop-hdfs-datanode-ps3765.log.2:{"@timestamp":"2017-09-13T00:56:20.933Z","source_host":"ps3765.example.com","file":"FsDatasetImpl.java","method":"updateReplicaUnderRecovery","level":"INFO","line_number":"2512","thread_name":"IPC Server handler 6 on 50020","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"updateReplica: BP-550436645-17.142.147.13-1438988035284:blk_2172795728_1106150312, recoveryId=1107074793, length=65024, replica=ReplicaUnderRecovery, blk_2172795728_1106150312, RUR
> $ grep "initReplicaRecovery:" ps2204.dn.log 
> hadoop-hdfs-datanode-ps2204.log.1:{"@timestamp":"2017-09-13T00:56:20.691Z","source_host":"ps2204.example.com","file":"FsDatasetImpl.java","method":"initReplicaRecoveryImpl","level":"INFO","line_number":"2441","thread_name":"org.apache.hadoop.hdfs.server.datanode.BlockRecoveryWorker$1@5ae3cb26","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"initReplicaRecovery: blk_2172795728_1106150312, recoveryId=1107074793, replica=ReplicaWaitingToBeRecovered, blk_2172795728_1106150312, RWR
> hadoop-hdfs-datanode-ps2204.log.1:{"@timestamp":"2017-09-13T00:56:20.691Z","source_host":"ps2204.example.com","file":"FsDatasetImpl.java","method":"initReplicaRecoveryImpl","level":"INFO","line_number":"2497","thread_name":"org.apache.hadoop.hdfs.server.datanode.BlockRecoveryWorker$1@5ae3cb26","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"initReplicaRecovery: changing replica state for blk_2172795728_1106150312 from RWR to RUR","class":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","mdc":{}}
> $ grep "initReplicaRecovery:" ps3765.dn.log 
> hadoop-hdfs-datanode-ps3765.log.2:{"@timestamp":"2017-09-13T00:56:20.457Z","source_host":"ps3765.example.com","file":"FsDatasetImpl.java","method":"initReplicaRecoveryImpl","level":"INFO","line_number":"2441","thread_name":"IPC Server handler 5 on 50020","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"initReplicaRecovery: blk_2172795728_1106150312, recoveryId=1107074793, replica=ReplicaBeingWritten, blk_2172795728_1106150312, RBW
> hadoop-hdfs-datanode-ps3765.log.2:{"@timestamp":"2017-09-13T00:56:20.457Z","source_host":"ps3765.example.com","file":"FsDatasetImpl.java","method":"initReplicaRecoveryImpl","level":"INFO","line_number":"2441","thread_name":"IPC Server handler 5 on 50020","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"initReplicaRecovery: blk_2172795728_1106150312, recoveryId=1107074793, replica=ReplicaBeingWritten, blk_2172795728_1106150312, RBW
> hadoop-hdfs-datanode-ps3765.log.2:{"@timestamp":"2017-09-13T00:56:20.457Z","source_host":"ps3765.example.com","file":"FsDatasetImpl.java","method":"initReplicaRecoveryImpl","level":"INFO","line_number":"2497","thread_name":"IPC Server handler 5 on 50020","@version":1,"logger_name":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","message":"initReplicaRecovery: changing replica state for blk_2172795728_1106150312 from RBW to RUR","class":"org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl","mdc":{}}
> {noformat}
> P.S. HDFS-11499 was once suspected, but non-conclusive since we don't have all NN logs to know about the decommission.


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