[HDFS-6964] NN fails to fix under replication leading to data loss

• Type: Bug
• Status: Resolved
• Priority: Blocker
• Resolution: Duplicate
• Affects Version/s: 2.0.0-alpha, 3.0.0-alpha1
• Component/s: namenode
• Assignee: Unassigned
• Reporter: Daryn Sharp
• Created: 28/Aug/14 17:26
• Updated: 24/Aug/17 14:04
• Resolved: 24/Aug/17 14:04

Description

We've encountered lost blocks due to node failure even when there is ample time to fix the under-replication.

2 nodes were lost. The 3rd node with the last remaining replicas averaged 1 copy block per heartbeat (3s) until ~7h later when that node was lost resulting in over 50 lost blocks. When the node was restarted and sent its BR the NN immediately began fixing the replication.

In another data loss event, over 150 blocks were lost due to node failure but the timing of the node loss is not known so there may have been inadequate time to fix the under-replication unlike the first case.

Issue Links

• is duplicated by: HDFS-11960 Successfully closed files can stay under-replicated.