[HDFS-12725] BlockPlacementPolicyRackFaultTolerant fails with very uneven racks

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0
• Fix Version/s: 3.0.0
• Component/s: erasure-coding
• Labels: hdfs-ec-3.0-must-do
• Target Version/s: 3.0.0
• Hadoop Flags: Reviewed
• Assignee: Xiao Chen
• Reporter: Xiao Chen
• Created: 26/Oct/17 20:49
• Updated: 03/Nov/17 05:27
• Resolved: 03/Nov/17 04:53

Description

HDFS-12567 tries to fix the scenario where EC blocks may not be allocated in extremely rack-imbalanced cluster.

The added fall-back step of the fix could be improved to do a best-effort placement. This is more likely to happen in testing than in real clusters.

Issue Links

• relates to: HDFS-12567 BlockPlacementPolicyRackFaultTolerant fails with racks with very few nodes