title: release 0.22.0 available date: 2011-12-10

This release contains many bug fixes and optimizations compared to its predecessor 0.21.0. See the Hadoop 0.22.0 Release Notes for details. Alternatively, you can look at the complete change log for this release

Notes:

The following features are not supported in Hadoop 0.22.0.

  • Security.
  • Latest optimizations of the MapReduce framework introduced in the Hadoop 0.20.security line of releases.
  • Disk-fail-in-place.
  • JMX-based metrics v2.

Hadoop 0.22.0 features

  • HBase support with hflush and hsync.
  • New implementation of file append.
  • Symbolic links.
  • BackupNode and CheckpointNode.
  • Hierarchical job queues.
  • Job limits per queue/pool.
  • Dynamically stop/start job queues.
  • Andvances in new mapreduce API: Input/Output formats, ChainMapper/Reducer.
  • TaskTracker blacklisting.
  • DistributedCache sharing.