NAS stands for Network-attached Storage and is generally regarded as the storage server which is file-level. It is connected to a server and is mainly responsible to make sure that the access has been provided to a group of users. When it comes to storing and accessing the files, all the responsibilities are beard by the NAS which can be a software or a hardware. It provides data access to a heterogeneous group of clients.On the other side, HDFS is a distributed file system and is actually based on commodity hardware HDFS is the primary storage system of Hadoop. It designs to store very large files running on a cluster of commodity hardware.
The Hadoop Distributed File System runs under cluster architecture.
It mainly designed to work on the MapReduce task.
Here the Data stored local drives along with their blocks.
The Network Attached Storage can run under the individual machine.
Data should be stored in dedicated Hardware only.
It minimizing the redundancy.