Map tasks (the first part of the MapReduce system) work on relatively small portions of data Typically a single block
Question :
What happens when a running task fails in the hadoop... 1. Failed task data will be lost 2. the master will detect that failure and re-assign the work to a different node on the system 3. Access Mostly Uused Products by 50000+ Subscribers 4. 2 and 3 both are correct
These are the Hadoops Fault Tolerance feature - If a node fails, the master will detect that failure and re-assign the work to a different node on the system - Restarting a task does not require communication with nodes working on other portions of the data - If a failed node restarts, it is automatically added back to the system and assigned new tasks
Question :
If a node appears to be running slowly then ..... 1. the master can redundantly execute another instance of the same task 2. Result from the first to finish will be used 3. Access Mostly Uused Products by 50000+ Subscribers 4. 1 and 2 are correct
If a node appears to be running slowly, the master can redundantly execute another instance of the same task - Results from the first to finish will be used
1. Hadoop API will convert the data to the type that is needed by the reducer. 2. Data input/output inconsistency cannot occur. A preliminary validation check is executed prior to the full execution of the job to ensure there is consistency. 3. Access Mostly Uused Products by 50000+ Subscribers 4. A real-time exception will be thrown and map-reduce job will fail
1. Yes, there is a special data type that will suppress job output 2. No, map reduce job will always generate output. 3. Access Mostly Uused Products by 50000+ Subscribers 4. Yes, but only during map execution when reducers have been set to zero
1. Ability to store large amount of data 2. Ability to process data on the cluster of the machines without copying all the data over 3. Access Mostly Uused Products by 50000+ Subscribers 4. Ability to process large amounts of data in parallel