SNO Parameter       NAS           SAN
1 Known as It is also called Network Attached Storage It is also called Storage Area Network
2 File or Block based NAS is file based protocol SAN  is block based protocol
3 Type of protocol NAS has CIFS and NFS protocols SAN has FC and iSCSI protocol
4 Cost of protocol NAS is comparatively less expensive than NAS  because of FC SAN is expensive solution because of FC
5 End Users   NAS end users are mid scale enterprises SAN end users are large scale enterprises
6 Security NAS is less secure than SAN because ethernet frames can be easily hacked. SAN is more secure than NAS because SAN has FC (optical rays cannot be hacked) which cannot be hacked.
7 Fastness NAS is comparatively slower than SAN as filesystem is pre-formatted SAN is comparatively faster than NAS  as filesystem is formatted at client side.