[HDFS-27] RPC on Datanode blocked forever.

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem

Environment

Java SE 1.6.0-b105 on Linux 2.6.x

• Assignee: Unassigned
• Reporter: Raghu Angadi
• Created: 17/Nov/08 22:52
• Updated: 03/Mar/11 02:03
• Resolved: 03/Mar/11 02:03

Description

We recently noticed a number of datanodes got stuck. The main thread that sends heartbeats and block reports is blocked in select() in side blockReport() RPC. I will add a stack trace in the next comment.

I am not sure why select was blocked forever since there is no connection open to NameNode. In fact, NN was restarted in between. It could be some JDK bug or a Hadoop bug.