Storage Area Networks (SANs) and Network Attached Storage (NAS) both
provide networked storage solutions. A NAS is a single storage device
that operates on data files, while a SAN is a local network of multiple
devices.
The differences between NAS and SAN can be
seen when comparing their cabling and how they're connected to the
system, as well as how communication to the device occurs.
SAN vs. NAS Technology
A NAS unit includes a dedicated hardware device that connects to a local area network, usually through an Ethernet connection.
This
NAS server authenticates clients and manages file operations in much
the same manner as traditional file servers, through well-established
network protocols.
To reduce the costs that occur with
traditional file servers, NAS devices generally run an embedded
operating system on simplified hardware and lack peripherals like a
monitor or keyboard.
A SAN commonly utilizes Fibre
Channel interconnects and connects a set of storage devices that are
able to share data with one another.
SAN vs. NAS Usage Models
The
administrator of a home or small business network can connect one NAS
device to their local area network. The NAS maintains its own IP address
comparable to computers and other TCP/IP devices. Using a software
program that is provided with the NAS hardware, the network
administrator can set up automatic or manual backups and file copies
between the NAS and all the other connected devices.
The
NAS holds many gigabytes or terabytes of data. Administrators can add
additional storage capacity to their network by installing additional
NAS devices, although each NAS operates independently.
Administrators
of large enterprise networks may require many terabytes of centralized
file storage or extremely high-speed file transfer operations.
Where
installing an army of many NAS devices is not a practical option,
administrators can instead install a SAN containing a high-performance
disk array to provide the needed scalability and performance.
SAN/NAS Convergence
As
internet technologies like TCP/IP and Ethernet have proliferated
worldwide, some SAN products are making the transition from Fibre
Channel to the same IP-based approach NAS uses. Also, with the rapid
improvements in disk storage technology, today's NAS devices now offer
capacities and performance that once were only possible with SAN.
These two industry factors have led to a partial convergence of NAS and SAN approaches to network storage.
Source: Bradley Mitchell
