[HDFS-4621] additional logging to help diagnose slow QJM logSync

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.0.3-alpha
• Fix Version/s: 2.1.0-beta
• Component/s: ha, qjm
• Target Version/s: 2.1.0-beta
• Hadoop Flags: Reviewed
• Assignee: Todd Lipcon
• Reporter: Todd Lipcon
• Created: 21/Mar/13 01:27
• Updated: 03/Sep/14 22:46
• Resolved: 27/Mar/13 18:44

Description

I've been working on diagnosing an issue with a cluster which is seeing slow logSync calls occasionally to QJM. Adding a few more pieces of logging would help this:

• in the warning messages on the client side leading up to a timeout, include which nodes have responded and which ones are still pending
• on the server side, when we actually call FileChannel.force, log a warning if the sync takes longer than 1 second