Your servers’ hard disks fill to capacity and your database runs out of space. You do not have money in the budget for more disk space right now, but you do have plenty of disk space on one of your file servers. Can SQL Server use this disk space for database files?
Answer – Yes, just turn on trace flag 1807, and then create secondary data files on the remote server using the UNC filename convention (\\server\share\filename.ext).
(Yes, you can use the remote drives by enabling trace flag 1807. Trace flag 3205 does exist, but it is for disabling hardware compression for tape drives.)