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Posts: 3
Registered: ‎10-20-2016

HBase exportSnapshot missing hfiles

[ Edited ]

We are using Cloudera CDH 5.12.1 on Ubuntu Xenial 16.04

 

hadoop 2.6.0+cdh5.12.1+2540-1.cdh5.12.1.p0.3~xenial-cdh5.12.1
hbase 1.2.0+cdh5.12.1+365-1.cdh5.12.1.p0.3~xenial-cdh5.12.1

 

We have 2 distinct Hadoop/HBase clusters which use Kerberos Authentication from the same realm

We take Nightly HBase snapshots of all our tables on our primary cluster and are attempting to use the ExportSnapshot utility to transfer our HBase data to our backup cluster for offline backups and a few other uses. This had been working fine for some time using an older version of CDH but since our upgrade to 5.12.1 and the securing of our cluster with Kerberos we have run into and issue that I just can not figure out.

 

We have 12 tables that we serial snapshot and attempt to export. Some of these tables are quite large and the distcp/export process takes many hours. The large tables always fail during the Verify Snapshot Integrity step. The export always says that it can not find the hfile on the remote site. By turning on hadoop and hbase debugging I see that the hfiles are copied over to the remote site but then deleted on the remote site before the exportSnapshot is completed. This makes the export fail. What I can not figure out is what process on the remote side is deleteing the hfiles outside of the export snapshot. I have a theory it may be something to do with the hfile cleaner task but can not verify that in any way.

 

I was wondering if anyone else has experinced this or has an idea as to what might be going on.

 

This is the command we use the export the HBase snapshots

 

HADOOP_OPTS="-Dmapred.job.map.memory.mb=4096 -Dmapreduce.map.memory.mb=4096 HADOOP_HEAPSIZE=4096 hbase org.apache.hadoop.hbase.snapshot.ExportSnapshot -chuser hbase -chgroup hbase -copy-to hdfs://hdnn001.ch1.tnbsound.com:8020/hbase -snapshot 20171207210001.idx_entity_dma

 

This is the hbase log that shows the error 

 

2017-12-21 06:04:07,947 INFO [main] snapshot.ExportSnapshot: Finalize the Snapshot Export
2017-12-21 06:04:08,306 INFO [main] snapshot.ExportSnapshot: Verify snapshot integrity
2017-12-21 06:04:08,310 INFO [main] Configuration.deprecation: fs.default.name is deprecated. Instead, use fs.defaultFS
2017-12-21 06:05:04,333 ERROR [VerifySnapshot-pool1-t1] snapshot.SnapshotReferenceUtil: Can't find hfile: 5d3803fa1bd44fa7b035de9b6feb850a in the real (hdfs://hdnn001.ch1.tnbsound.com:8020/hbase/data/default/idx_entity_asset_subregion/35367cf285b59a1a66067fd168caf2b6/m/5d3803fa1bd44fa7b035de9b6feb850a) or archive (hdfs://hdnn001.ch1.tnbsound.com:8020/hbase/archive/data/default/idx_entity_asset_subregion/35367cf285b59a1a66067fd168caf2b6/m/5d3803fa1bd44fa7b035de9b6feb850a) directory for the primary table.
2017-12-21 06:05:04,338 ERROR [main] snapshot.ExportSnapshot: Snapshot export failed
org.apache.hadoop.hbase.snapshot.CorruptedSnapshotException: Can't find hfile: 5d3803fa1bd44fa7b035de9b6feb850a in the real (hdfs://hdnn001.ch1.tnbsound.com:8020/hbase/data/default/idx_entity_asset_subregion/35367cf285b59a1a66067fd168caf2b6/m/5d3803fa1bd44fa7b035de9b6feb850a) or archive (hdfs://hdnn001.ch1.tnbsound.com:8020/hbase/archive/data/default/idx_entity_asset_subregion/35367cf285b59a1a66067fd168caf2b6/m/5d3803fa1bd44fa7b035de9b6feb850a) directory for the primary table.
at org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil.concurrentVisitReferencedFiles(SnapshotReferenceUtil.java:260)
at org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil.concurrentVisitReferencedFiles(SnapshotReferenceUtil.java:223)
at org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil.verifySnapshot(SnapshotReferenceUtil.java:200)
at org.apache.hadoop.hbase.snapshot.SnapshotReferenceUtil.verifySnapshot(SnapshotReferenceUtil.java:184)
at org.apache.hadoop.hbase.snapshot.ExportSnapshot.verifySnapshot(ExportSnapshot.java:836)
at org.apache.hadoop.hbase.snapshot.ExportSnapshot.run(ExportSnapshot.java:1035)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.hbase.snapshot.ExportSnapshot.innerMain(ExportSnapshot.java:1094)
at org.apache.hadoop.hbase.snapshot.ExportSnapshot.main(ExportSnapshot.java:1098)

 

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Posts: 23
Registered: ‎03-07-2017

Re: HBase exportSnapshot missing hfiles

Maybe as a workaround you can write to another directory /tmp and once distcp is completed, move the snapshot and archive to proper locations.

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