Question : SAN

hi experts

I need a help about SAN
I want a basic and short information about SAN and what is different between SAN and NAS
what are the main component of SAN and what is the SAN switch is it different form any other
swithch finally what are the advantges of SAN

thanks

Answer : SAN

SAN and NAs are usually two different products

Nas is just a fileserver, somewhere to store files sat on the network.

SAN's are totally different beast you have a ruck of disks which are connected to a fibre switch, then you have fibre connections to servers. Using the SAN management software you split up the disks into logical drives(LUNS), you then allocate the luns to individual servers. The network cards come up with server at boot up and the luns appear as drives on each server.

The advantages of SANS are that you could actually have the boot disk on a LUN so a bit like serverless disks. also it is quite easy to add additional luns if you require extra space on a server providing you have available space or unallocated LUNS on the SAN.  

There is a similar product that does a way with the fibre network and uses iSCSI which uses ethernet this works in a similar way though I am uncertain of the details.

Hitachi EMC and HP all do various SAN soloutions

David