SAN is a general term used to denote a shared device setup. So, if you have a library attached to two servers through fiber channel, we call it SAN. Now, if you have Backup Exec installed on both these servers, and you are backing up local data, it is dumped to the library through fiber channel, making it fast. Please note, we are just talking about BE with no license, here. So, SAN works even if SSO license is not there. Now, when you have SSO license added to a Backup Exec server, it gives you the additional capability of centralizing the solution where you have all different Backup Exec servers managed by a central database. So, one of the servers where you install SSO becomes a primary server, and all other servers are secondary. Technically no difference, all are Backup Exec servers, but a server designated as primary holds the device and media information and also catalogs. The secondary servers send the informaiton about their devices to primary server's database and management of devices and media becomes easier. Now, if you do a backup of a remote machine from one of these media servers, and only RAWS is installed on that target server, no BE, you dont leverage SAN then, and data flows to the media server through LAN and then media server dumps it to the device through fiber. If SAN is to be leveraged, you need to install BE on all servers and add SSO license to them, designate one as primary and rest as secondary and then run backups locally. In order to designate a server as primary or secondary, use beutility as in following document:
http://support.veritas.com/docs/300213
Some other documents for your reference:
http://support.veritas.com/docs/343614
http://support.veritas.com/docs/268678
Please also go through the administrator's guide for more information.
Please mark it a solution, if this helps.
Thanks