FUNDAMENTALS OF COMPUTER

Detailed explanation-1: -HDFS performs replication to provide Fault Tolerant and to improve data reliability. HDFS is all about data so one can not afford data loss in any circumstances.

Detailed explanation-2: -Why HDFS performs replication, although it results in data redundancy? HDFS provides reliable, scalable and fault tolerant data processing system. Blocks which are present in different data nodes. These data nodes are present in different racks as well.

Detailed explanation-3: -Q 2-What is are true about HDFS? A-HDFS filesystem can be mounted on a local client’s Filesystem using NFS. B-HDFS filesystem can never be mounted on a local client’s Filesystem. C-You can edit a existing record in HDFS file which is already mounted using NFS.

Detailed explanation-4: -Data redundancy. By default, two copies of the data are stored in HDFS. If a machine in the cluster becomes unavailable or fails, the SAS LASR Analytic Server instance on another machine in the cluster retrieves the data from a redundant block and loads the data into memory.

Detailed explanation-5: -Data Replication. HDFS is designed to reliably store very large files across machines in a large cluster. It stores each file as a sequence of blocks; all blocks in a file except the last block are the same size. The blocks of a file are replicated for fault tolerance.