We back up our SQL Server databases to a central storage machine using UNC paths in the
BACKUP statement (BACKUP DATABASE db1 TO DISK='\\storage\Backups\db1\db1.bak...). For a while, backups were failing with the message:
BackupDiskFile::RequestDurableMedia: failure on backup device '\\storage\Backups\db1\db1.bak'. Operating system error 64(The specified network name is no longer available.).
I struggled for a while to find a solution and finally found this thread on www.msce.ms. Unfortunately that seems to have disappeared, so this is a summary of what that thread recommended (and what worked for me):
- Open the registry of the SQL Server machine and navigate to HKLM\System\CurrentControlSet\Services\lanmanworkstation\parameters
- Create a new DWORD value named SessTimeout (if it's already there I guess you can change the value but it wasn't there on any server I was having the problem with).
- Set the value to decimal 600 (hex 0x258) - I believe this is seconds.
This corrected the problem for me (on two machines I had to bump the value to 900) and seems to have no ill effects on the rest of the server.