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Home » Unlabelled » How NameNode Handles data node failures? | Hadoop Framework Questions
How NameNode Handles data node failures? | Hadoop Framework Questions
Through checksums. every data has a record followed by a checksum. if checksum doesnot match with the original then it reports an data corrupted error.
If the NameNode does not receive a heart beat signal (send every 3 secs) from the DataNode for a period of time (5 mins). NameNode assumes that the particular DataNode is stale. It is controlled by the properties dfs.namenode.heartbeat.recheck-interval = 3000000 (millisecs) & dfs.heartbeat.interval = 3 (secs)
If the NameNode does not receive a heart beat signal (send every 3 secs) from the DataNode for a period of time (5 mins). NameNode assumes that the particular DataNode is stale. It is controlled by the properties dfs.namenode.heartbeat.recheck-interval = 3000000 (millisecs) & dfs.heartbeat.interval = 3 (secs)
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