[HDFS-5037] Active NN should trigger its own edit log rolls

• Type: Improvement
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.1.0-beta, 3.0.0-alpha1
• Fix Version/s: 2.3.0
• Component/s: ha, namenode
• Target Version/s: 2.1.0-beta
• Assignee: Andrew Wang
• Reporter: Todd Lipcon
• Created: 26/Jul/13 15:26
• Updated: 12/May/16 18:17
• Resolved: 01/Nov/13 21:19

Description

We've seen cases where the SBN/2NN went down, and then users accumulated very very large edit log segments. This causes a slow startup time because the last edit log segment must be read fully to recover it before the NN can start up again. Additionally, in the case of QJM, it can trigger timeouts on recovery or edit log syncing because the very-large segment has to get processed within a certain time bound.

We could easily improve this by having the NN trigger its own edit log rolls on a configurable size (eg every 256MB)