[HADOOP-96] name server should log decisions that affect data: block creation, removal, replication

• Type: Improvement
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 0.1.0
• Fix Version/s: 0.2.0
• Assignee: Hairong Kuang
• Reporter: Yoram Arnon
• Created: 22/Mar/06 01:09
• Updated: 08/Jul/09 16:41
• Resolved: 06/May/06 00:08

Description

currently, there's no way to analyze and debug DFS errors where blocks disapear.
name server should log its decisions that affect data, including block creation, removal, replication:

• block <b> created, assigned to datanodes A, B, ...
• datanode A dead, block <b> underreplicated(1), replicating to datanode C
• datanode B dead, block <b> underreplicated(2), replicating to datanode D
• datanode A alive, block <b> overreplicated, removing from datanode D
• block <removed> from datanodes C, D, ...

that will enable me to track down, two weeks later, a block that's missing from a file, and to debug the name server.

extra credit:

• rotate log file, as it might grow large
• make this behaviour optional/configurable