What is the recommended HDFS replication factor for more cost-efficient, low-risk environments?

What is the recommended HDFS replication factor for more cost-efficient, low-risk environments?

• A. 1
• B. 2
• C. 3
• D. 4

Answer: (B)

In distributed file systems like HDFS (Hadoop Distributed File System), the replication factor is crucial for ensuring data availability and fault tolerance. A replication factor of 2 is often recommended for more cost-efficient, low-risk environments. This setting provides a balance between redundancy and resource utilization. When data is replicated twice, it means that each piece of data is stored on two different nodes in the cluster. This configuration offers a level of protection against data loss due to node failures, as one copy can remain accessible if another node goes down. At the same time, it reduces the storage overhead compared to a replication factor of 3 or higher. Using a replication factor of 3, while it further enhances fault tolerance, significantly increases the storage requirements, which may not be necessary in environments considered to have a lower risk of data loss. Similarly, higher replication factors lead to additional disk space usage and may impact performance by increasing the amount of data that needs to be written during operations. Thus, for environments that prioritize cost efficiency without sacrificing essential fault tolerance, a replication factor of 2 strikes an effective balance, making it the recommended choice.

In distributed file systems like HDFS (Hadoop Distributed File System), the replication factor is crucial for ensuring data availability and fault tolerance. A replication factor of 2 is often recommended for more cost-efficient, low-risk environments. This setting provides a balance between redundancy and resource utilization.

When data is replicated twice, it means that each piece of data is stored on two different nodes in the cluster. This configuration offers a level of protection against data loss due to node failures, as one copy can remain accessible if another node goes down. At the same time, it reduces the storage overhead compared to a replication factor of 3 or higher.

Using a replication factor of 3, while it further enhances fault tolerance, significantly increases the storage requirements, which may not be necessary in environments considered to have a lower risk of data loss. Similarly, higher replication factors lead to additional disk space usage and may impact performance by increasing the amount of data that needs to be written during operations.

Thus, for environments that prioritize cost efficiency without sacrificing essential fault tolerance, a replication factor of 2 strikes an effective balance, making it the recommended choice.