Following are differences between HDFS and NAS1.
o In HDFS Data Blocks are distributed across local drives of all machines in a cluster. Whereas in NAS data is stored
on dedicated hardware.
o HDFS is designed to work with MapReduce System, since computation is moved to data. NAS is not suitable for MapReduce since data is stored separately from the computations.
o HDFS runs on a cluster of machines and provides redundancy using replication protocol. Whereas NAS is provided by a single machine therefore does not provide data redundancy.