With LAN-Free Backup typically the Application Server will backup its own data from disk to tape. Data flow over the SAN is much faster than over the LAN and can relieve LAN congestion.
If this particular application ran from 9-5, so the application server now sits idle overnight, so you can back up. It can read its own data, it can write its own data to tape, it will build its own tape catalogue, its own index, the index then gets copied back. But if our application was running 24/7 we probably don’t want our application server being responsible for doing the backup because its going to take up too many CPU cycles.
At this point we can separate out the media server component.