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what is the difference between SAN,NAS and DAS?

I would like to know the difference between SAN and NAS (explained in basic English before getting too technical).

I saw a few site on this. They have topologies and difference diagrams. I have a vague understanding, but need to make that concrete.

So if somebody can take it from conceptual differences to the technical differences to the implementation differences, it would be great.


2 Answers 2


Normally a NAS provides an NFS/SMB share, a SAN provides disks to a system that it uses as disks, rather than a shared area to write to.

So, if you want a document storage area for your colleagues or some source code etc, a NAS is cheaper, because the cheaper ones run a cut down version of linux and pump out the shares using samba and NFS.

Sans are more expensive as they are often fibre based, and you get in effect a direct connection to a portion of disk for a given machine you can treat as your very own.


Wikipedia is very much your friend and mine:

SAN - Storage Area Network

NAS - Networked Attached Storage

One way to loosely conceptualise the difference between a NAS and a SAN is that a NAS appears to the client OS (operating system) as a file server (the client can map network drives to shares on that server) whereas a disk available through a SAN still appears to the client OS as a disk, visible in disk and volume management utilities (along client's local disks), and available to be formatted with a file system and mounted.

(All credit for the above text goes to Wikipedia, not me!)