[HADOOP-3232] Datanodes time out

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.16.2
• Fix Version/s: 0.18.0

Environment

10 node cluster + 1 namenode

• Hadoop Flags: Reviewed
• Release Note: Changed 'du' command to run in a seperate thread so that it does not block user.
• Assignee: Johan Oskarsson
• Reporter: Johan Oskarsson
• Created: 10/Apr/08 14:57
• Updated: 08/Jul/09 16:43
• Resolved: 22/May/08 18:22

Description

I recently upgraded to 0.16.2 from 0.15.2 on our 10 node cluster.
Unfortunately we're seeing datanode timeout issues. In previous versions we've often seen in the nn webui that one or two datanodes "last contact" goes from the usual 0-3 sec to ~200-300 before it drops down to 0 again.

This causes mild discomfort but the big problems appear when all nodes do this at once, as happened a few times after the upgrade.
It was suggested that this could be due to namenode garbage collection, but looking at the gc log output it doesn't seem to be the case.

Issue Links

• is related to: HADOOP-4584 Slow generation of blockReport at DataNode causes delay of sending heartbeat to NameNode