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https://issues.apache.org/jira/browse/HDFS-8344?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15723538#comment-15723538
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Wei-Chiu Chuang commented on HDFS-8344:
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I believe I saw a variant of this bug.
Symptom: HBase WAL file's last block went missing. These blocks are 83 bytes
according to NameNode, and cannot be deleted, cannot be recovered via hdfs
debug -recoverLease command.
I am aware at least one scenario where this can happen, when performance volume
hot-swap. I suppose other operations such as datanode decommissioning might
also lead to the same symptom.
When this happens, the NameNode has log like this:
{quote}
2016-10-12 16:39:32,885 INFO
org.apache.hadoop.hdfs.server.namenode.FSNamesystem: Recovering [Lease.
Holder: DFSClient_NONMAPREDUCE_751860335_1, pendingcreates: 3],
src=/hbase/WALs/hadoopdev6.example.com,60020,1465915112353-splitting/hadoopdev6.example.com%2C60020%2C1465915112353.null0.1471340470256
2016-10-12 16:39:32,885 INFO
org.apache.hadoop.hdfs.server.namenode.FSNamesystem: recoverLease: [Lease.
Holder: DFSClient_NONMAPREDUCE_751860335_1, pendingcreates: 3],
src=/hbase/WALs/hadoopdev6.example.com,60020,1465915112353-splitting/hadoopdev6.example.com%2C60020%2C1465915112353.null0.1471340470256
from client DFSClient_NONMAPREDUCE_751860335_1
2016-10-12 16:39:32,885 DEBUG org.apache.hadoop.ipc.Server: IPC Server handler
0 on 8020: org.apache.hadoop.hdfs.protocol.ClientProtocol.recoverLease from
192.168.4.86:35276 Call#708331 Retry#0 for RpcKind RPC_PROTOCOL_BUFFER
2016-10-12 16:39:32,885 DEBUG org.apache.hadoop.ipc.Server: got #708331
2016-10-12 16:39:32,886 WARN BlockStateChange: BLOCK*
BlockInfoUnderConstruction.initLeaseRecovery: No blocks found, lease removed.
2016-10-12 16:39:32,886 WARN org.apache.hadoop.hdfs.StateChange: DIR*
NameSystem.internalReleaseLease: File
/hbase/WALs/hadoopdev6.example.com,60020,1465915112353-splitting/hadoopdev6.example.com%2C60020%2C1465915112353.null0.1471340470256
has not been closed. Lease recovery is in progress. RecoveryId = 1099610544470
for block blk_1074528903_1099610239882{blockUCState=UNDER_RECOVERY, primary
NodeIndex=-1, replicas=[]}
2016-10-12 16:39:32,887 DEBUG org.apache.hadoop.ipc.Server: IPC Server handler
0 on 8020: responding to
org.apache.hadoop.hdfs.protocol.ClientProtocol.recoverLease from
192.168.4.86:35276 Call#708331 Retry#0 Wrote 36 bytes.
2016-10-12 16:39:32,887 DEBUG org.apache.hadoop.ipc.Server: IPC Server handler
0 on 8020: responding to
org.apache.hadoop.hdfs.protocol.ClientProtocol.recoverLease from
192.168.4.86:35276 Call#708331 Retry#0
2016-10-12 16:39:32,887 DEBUG org.apache.hadoop.ipc.Server: Served:
recoverLease queueTime= 0 procesingTime= 2
{quote}
And the lease recover would repeat every one minute non-stop.
> NameNode doesn't recover lease for files with missing blocks
> ------------------------------------------------------------
>
> Key: HDFS-8344
> URL: https://issues.apache.org/jira/browse/HDFS-8344
> Project: Hadoop HDFS
> Issue Type: Bug
> Components: namenode
> Affects Versions: 2.7.0
> Reporter: Ravi Prakash
> Assignee: Ravi Prakash
> Attachments: HDFS-8344.01.patch, HDFS-8344.02.patch,
> HDFS-8344.03.patch, HDFS-8344.04.patch, HDFS-8344.05.patch,
> HDFS-8344.06.patch, HDFS-8344.07.patch, HDFS-8344.08.patch,
> HDFS-8344.09.patch, HDFS-8344.10.patch, TestHadoop.java
>
>
> I found another\(?) instance in which the lease is not recovered. This is
> reproducible easily on a pseudo-distributed single node cluster
> # Before you start it helps if you set. This is not necessary, but simply
> reduces how long you have to wait
> {code}
> public static final long LEASE_SOFTLIMIT_PERIOD = 30 * 1000;
> public static final long LEASE_HARDLIMIT_PERIOD = 2 *
> LEASE_SOFTLIMIT_PERIOD;
> {code}
> # Client starts to write a file. (could be less than 1 block, but it hflushed
> so some of the data has landed on the datanodes) (I'm copying the client code
> I am using. I generate a jar and run it using $ hadoop jar TestHadoop.jar)
> # Client crashes. (I simulate this by kill -9 the $(hadoop jar
> TestHadoop.jar) process after it has printed "Wrote to the bufferedWriter"
> # Shoot the datanode. (Since I ran on a pseudo-distributed cluster, there was
> only 1)
> I believe the lease should be recovered and the block should be marked
> missing. However this is not happening. The lease is never recovered.
> The effect of this bug for us was that nodes could not be decommissioned
> cleanly. Although we knew that the client had crashed, the Namenode never
> released the leases (even after restarting the Namenode) (even months
> afterwards). There are actually several other cases too where we don't
> consider what happens if ALL the datanodes die while the file is being
> written, but I am going to punt on that for another time.
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