[HADOOP-4771] FSImage saveFSImage() will have problem.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 0.18.2, 0.19.0
• Fix Version/s: 0.20.0
• Hadoop Flags: Reviewed
• Assignee: Ruyue Ma
• Reporter: Ruyue Ma
• Created: 04/Dec/08 06:39
• Updated: 08/Jul/09 16:43
• Resolved: 17/Dec/08 01:02

Description

When you format the namenode , hadoop will call FSImage.saveFsImage(). saveFsImage includes the following code:

out.writeLong(fsDir.rootDir.numItemsInTree());

When format, the fsDir.rootDir.numItemsInTree() should be 1 (it include the rootdir). But now fsDir.rootDir.numItemsInTree() is 0.

The reason why the bug is not simply discovered or triggered is the code in FSImage.saveFsImage().->saveINode2Image().

} else { // write directory inode
out.writeShort(0); // replication

Because the directory doesn't have replication factor, so here is 0. This will cause loadFilesUnderConstruction() will not load any files when hadoop fisrt starts up after format.

Issue Links

• blocks: HDFS-199 add replication factor for hdfs directory