Have you ever tried a test restore?

If you truncate the log without backing it up (as with your statement), you have broken the chain of tran logs and any subsequent tran log backup is worthless. I suggest instead backing up the tran log before your full backup. That will truncate the log and make one fewer log file to apply when recovering from the backup.

If you let your database and log files autogrow only to constantly reshrink them, you're harming performance in two ways:

• This virtually guarantees that the files will become fragmented on disk, causing the drive heads to have to stop reading or writing and reposition often.
• Your files will be forced to autogrow often, which uses CPU cycles (and stalls disk I/O).

--Jonathan