[HDFS-14349] Edit log may be rolled more frequently than necessary with multiple Standby nodes

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Component/s: ha, hdfs, qjm
• Labels: multi-sbnn
• Target Version/s: 3.2.5
• Assignee: Ekanth Sethuramalingam
• Reporter: Erik Krogen
• Created: 08/Mar/19 23:05
• Updated: 12/Jul/22 16:08

Description

When HDFS-14317 was fixed, we tackled the problem that in a cluster with in-progress edit log tailing enabled, a Standby NameNode may never roll the edit logs, which can eventually cause data loss.

Unfortunately, in the process, it was made so that if there are multiple Standby NameNodes, they will all roll the edit logs at their specified frequency, so the edit log will be rolled X times more frequently than they should be (where X is the number of Standby NNs). This is not as bad as the original bug since rolling frequently does not affect correctness or data availability, but may degrade performance by creating more edit log segments than necessary.

Issue Links

• duplicates: HDFS-13189 Standby NameNode should roll active edit log when checkpointing
• is broken by: HDFS-14317 Standby does not trigger edit log rolling when in-progress edit log tailing is enabled
• is related to: HDFS-14378 Simplify the design of multiple NN and both logic of edit log roll and checkpoint