Microsoft® SQL Server 2012 Unleashed

Network Shares

SQL Server 2012 allows the use of both mapped network drives and Universal Naming Convention (UNC) paths in the backup device filename. A mapped network drive must be mapped as a network drive in the session in which SQL Server is running. This is prone to error and generally not recommended. UNC paths are much simpler to administer. With UNC backup devices, the SQL Server service account must be able to see the UNC path on the network. This can be accomplished by granting the service account full control permission on the share or by making the service account a member of the Administrators group on the remote computer.

Keep in mind that backups performed on a network share should be done on a dedicated or high-speed network connection, ...