[HDFS-9841] FileDiff's skipped by hdfs snapshotDiff

• Type: Bug
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.5.0
• Component/s: snapshots
• Assignee: John Zhuge
• Reporter: Alex Ivanov
• Created: 21/Feb/16 23:13
• Updated: 03/Mar/16 03:47

Description

Summary
As described in HDFS-9197, FileDiff's get created based on changes in a file's modified or access time. In Hadoop 2.5, the method metadataEquals was added to org.apache.hadoop.hdfs.server.namenode.INodeFileAttributes. The hdfs snapshotDiff command seems to use the method to show a list of snapshot metadata diff's, but because the method doesn't check for the times, you CANNOT see the time-based FileDiff's in the comparison. This used to work before Hadoop 2.5. I see the new behavior as problematic because the user no longer has an accurate picture of all the Namenode metadata created for a snapshot unless he looks at the fsimage.

Configuration:
CDH 5.5.1 (Hadoop 2.6)

Issue Links

• is a clone of: HDFS-9197 Snapshot FileDiff added to last snapshot when INodeFile accessTime field is updated