[HDFS-3407] When "dfs.datanode.directoryscan.interval" is configured to 0 DN get shutdown but when configured to -1/ less than 0 values directory scan is disabled

• Type: Bug
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 2.0.0-alpha
• Assignee: Unassigned
• Reporter: J.Andreina
• Created: 11/May/12 15:48
• Updated: 23/May/12 20:24

Description

Scenario 1:
===========

•configure "dfs.datanode.directoryscan.interval"= -1
•start NN and DN
Directory scan will be disabled if we configure a value less than zero. write will be successful and DN will not be shutdown.
NN logs:
========

2012-04-24 20:45:48,783 INFO org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl: Registered FSDatasetState MBean
2012-04-24 20:45:48,787 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Periodic Directory Tree Verification scan is disabled because verification is turned off by configuration.
2012-04-24 20:45:48,787 INFO org.apache.hadoop.hdfs.server.datanode.fsdataset.impl.FsDatasetImpl: Adding block pool BP-1927320586-10.18.40.117-1335280525860
2012-04-24 20:45:48,874 INFO org.apache.hadoop.hdfs.server.datanode.DataNode: Block pool BP-1927320586-10.18.40.117-1335280525860 (storage id DS-1680920264-10.18.40.117-50076-1335280548385) service to HOST-10-18-40-117/10.18.40.117:9000 beginning handshake with NN
20

Scenario 2:
============

•configure "dfs.datanode.directoryscan.interval"=0
•Start NN and DN
Data node gets shutdown and throws IllegalArgumentException

java.lang.IllegalArgumentException: n must be positive
	at java.util.Random.nextInt(Random.java:250)
	at org.apache.hadoop.hdfs.server.datanode.DirectoryScanner.start(DirectoryScanner.java:241)
	at org.apache.hadoop.hdfs.server.datanode.DataNode.initDirectoryScanner(DataNode.java:489)
	at org.apache.hadoop.hdfs.server.datanode.DataNode.initPeriodicScanners(DataNode.java:435)
	at org.apache.hadoop.hdfs.server.datanode.DataNode.initBlockPool(DataNode.java:800)
	at org.apache.hadoop.hdfs.server.datanode.BPOfferService.verifyAndSetNamespaceInfo(BPOfferService.java:308)
	at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.connectToNNAndHandshake(BPServiceActor.java:217)
	at org.apache.hadoop.hdfs.server.datanode.BPServiceActor.run(BPServiceActor.java:657)
	at java.lang.Thread.run(Thread.java:619)

EXPECTED:
============
Code:
=====

if (conf.getInt(DFS_DATANODE_SCAN_PERIOD_HOURS_KEY,
                    DFS_DATANODE_SCAN_PERIOD_HOURS_DEFAULT) < 0) {
      reason = "verification is turned off by configuration";
    } 

In the above code instead of checking only for <0 values <=0 can be checked.

Attached the logs for both the scenarios