Consultor Eletrônico

Status: Technically Reviewed

GOAL:

What is Storage Area Network (SAN)

GOAL:

What is Network Attached Storage (NAS)

GOAL:

A summary of the features of Storage Area Network (SAN) and Network Attached Storage(NAS) network storage options.

FIX:

These options seem to be similar but they are quite different from each other. Think of them as different evolutions of file servers.
Storage-area Network (SAN):

SAN is a dedicated high-speed network for inter-connecting
different kinds of storage devices (such as tape libraries and
disk arrays) to server computers.

The dedicated network is used only for storage access. SSA,
Fibre-Channel and FDDI are commonly used for this network
interconnect, but other technologies are also used.

In the long run, FC and FDDI will go away, to be replaced by 10
GB and faster Ethernet connections. Current technology allows
faster than processor bus speeds in the laboratory environment,
and might already be available commercially.

The main advantages to SAN are that you can manage all storage
entirely from the central storage system, and several servers can
share parts of the same SAN. Some disadvantages are that the
controllers you must install on the servers can be expensive, and
there are inter-operability problems among vendors.

Network Attached Storage (NAS):

NAS is typically storage on an Ethernet LAN. It is less expensive
than a SAN. Performance can be reasonably good with a dedicated
Gigabit Ethernet, and poor when NAS is on the same slow LAN as
everything else. Ethernet is cheap.

Many NAS implementations use NFS and SMB as protocols. At a
conceptual level, the two are different ways to implement the
same thing. Both architectures produce the temptation to focus
primarily on managing capacity. If you do that, performance
suffers greatly.

In the long run, NAS and SAN might merge, and vendors distinguish
themselves by different tradeoffs of cost, performance,
reliability, and management capability.