In Hadoop, there are multiple data nodes that hold data. During the processing of map and reduce methods data may
Hadoop provides a utility called Distributed Cache to improve the performance of jobs by caching the files used by applications.
It is a trick question. In Distributed Cache, it is not allowed to make any changes to a file. This
In HDFS, DataNode supports hot swappable drives. With a swappable drive we can add or replace HDFS data volumes while
There are two important configuration files in a Hadoop cluster:
<li><strong>Default Configuration</strong>: There are core-default.xml, hdfs-default.xml and mapred-default.xml files in which we specify the default configuration for Hadoop cluster. These are read only files.</li>
<li><strong>Custom Configuration</strong>: We have site-specific custom files like core-site.xml, hdfs-site.xml, mapred-site.xml in which we can specify the site-specific configuration.
All the Jobs in Hadoop and HDFS implementation uses
In Hadoop, TaskTracker is the one that uses high memory to perform a task. We can configure the TastTracker to
Partition phase runs between Map and Reduce phase. It is an optional phase. We can create a custom partitioner by
The main differences between RDBMS and HBase data model are as follows: Schema: In RDBMS, there is a schema of
A Checkpoint node in HDFS periodically fetches fsimage and edits from NameNode, and merges them. This merge result is called
Backup Node in HDFS is similar to Checkpoint Node. It takes the stream of edits from NameNode. It keeps these