Apache Hadoop 2.7.1 Release Notes

These release notes cover new developer and user-facing incompatibilities, important issues, features, and major improvements.

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• HDFS-8486 | Blocker | DN startup may cause severe data loss

Public service notice:

• Every restart of a 2.6.x or 2.7.0 DN incurs a risk of unwanted block deletion.
• Apply this patch if you are running a pre-2.7.1 release.

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• HDFS-8270 | Major | create() always retried with hardcoded timeout when file already exists with open lease

Proxy level retries will not be done on AlreadyBeingCreatedExeption for create() op.

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• HDFS-8226 | Blocker | Non-HA rollback compatibility broken

Non-HA rollback steps have been changed. Run the rollback command on the namenode (bin/hdfs namenode -rollback) before starting cluster with ‘-rollback’ option using (sbin/start-dfs.sh -rollback).