Executing the code below in SQL Server 2008 will throw an error message:

BACKUP LOG ‘MyDatabase’ WITH TRUNCATE_ONLY
Msg 155, Level 15, State 1, Line 44
'TRUNCATE_ONLY' is not a recognized BACKUP option.

It was deprecated in SQL Server 2008.

 Some options for SQL Server 2008 are :

 1)    BACKUP LOG [DBNAME] TO DISK='NUL'

This will break the  transaction log chain. Therefore a Full backup is required after the command.

2)    Switch to Simple Recovery and then switch back to Full Recovery. This will required a Full backup to restart a new  transaction log chain

 3)  DBCC SHRINKFILE(Test_Log)    . This option causes fragmentation , but does the job when it comes to reclaiming space.   You might find it doesn’t shrink – in that case check for open transactions.

4) Take regular Transaction Log backups while maintaining a small log file size

 The choice will depend on the circumstances.

Author: Jack Vamvas (http://www.sqlserver-dba.com)