[HDFS-13957] Fix incorrect option used in description of InMemoryAliasMap

• Type: Bug
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 3.1.1
• Fix Version/s: 3.2.0, 3.1.2, 3.3.0
• Component/s: documentation
• Target Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Yiqun Lin
• Reporter: Yiqun Lin
• Created: 04/Oct/18 02:12
• Updated: 05/Oct/18 02:20
• Resolved: 05/Oct/18 01:56

Description

The incorrect option was used in description of InMemoryAliasMap.

This is a LevelDB-based alias map that runs as a separate server in Namenode. The alias map itself can be created using the fs2img tool using the option -Ddfs.provided.aliasmap.leveldb.path=file:///path/to/leveldb/map/dingos.db -o org.apache.hadoop.hdfs.server.common.blockaliasmap.impl.LevelDBFileRegionAliasMap as in the example above.

Here -o should be -b, -o is specified for output directory of generated fsimage. -b is for block output class. The right usage showed in the doc:

hadoop org.apache.hadoop.hdfs.server.namenode.FileSystemImage \
  -Ddfs.provided.aliasmap.leveldb.path=/path/to/leveldb/map/dingos.db \
  -b org.apache.hadoop.hdfs.server.common.blockaliasmap.impl.LevelDBFileRegionAliasMap \
  -o file:///tmp/name \
  -u CustomResolver \
  hdfs://enfield/projects/ywqmd/incandenza