[HDFS-2794] HA: Active NN may purge edit log files before standby NN has a chance to read them

• Type: Sub-task
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: HA branch (HDFS-1623)
• Fix Version/s: HA branch (HDFS-1623)
• Component/s: ha, namenode
• Target Version/s: HA branch (HDFS-1623)
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Aaron Myers
• Created: 16/Jan/12 06:44
• Updated: 07/Feb/12 12:58
• Resolved: 07/Feb/12 01:39

Description

Given that the active NN is solely responsible for purging finalized edit log segments, and given that the active NN has no way of knowing when the standby reads edit logs, it's possible that the standby NN could fail to read all edits it needs before the active purges the files.