[HADOOP-1613] The dfs webui (dfshealth) shows "Last Contact" as a negative number

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 0.14.0
• Assignee: Dhruba Borthakur
• Reporter: Dhruba Borthakur
• Created: 14/Jul/07 05:51
• Updated: 08/Jul/09 16:42
• Resolved: 16/Jul/07 18:57

Description

The dfshealth.jsp displays the number of seconds that have elapse since the namenode got a heartbeat from a datanode. When the number of nodes in the cluster are huge, may of these values are seen to be negative numbers.

The FSNamesystem returns the timestamp when the namenode had last-heard from a datanode. The dfshealth.jsp gets the current system time and then subtracts the timestamp returned by the Namenode. This ordering of retrieving timestamps cause this problem.