I was recently asked some questions about NAS’s and SANs and what their differences/similarities were. I could think about 1 main difference, but not too much after that:
- A NAS (network attached system), is a server with a bunch of hard drives in it. There is a special O/S that goes on it that manages the functions of the NAS and can allow for remote access either by CIFS or NFS. Usually they can manage things like quotas and backups using NDMP and do their own kind of disk formatting.
- A SAN (storage area network), usually describes an environment of storage nodes and backups usually using either iscsi (scsi over ethernet) or fibre. Mainly when people say SAN, they mean a SAN storage node. These nodes are usually a dumb box with a bunch of hard drives in it. In this you can do some basic things like partition out the disks and then assign it as local space to servers in the SAN. These partitions are usually called LUNs (logical unit number) and can be given out to anything on the SAN. When these LUNS are given out, they are just raw space that the server’s O/S will have to format itself.