anjang2k - Thursday, November 30, 2017 11:08 PM
Your log will be growing until you take regular log backups, like let's say every 1 hour for start - this will allow you later to do a point in time restores. You have to remember that mirroring does not protect you from all disaster scenarios (like delete data). Your database is already in FULL recovery model so might as well use it to it's full potential in terms of protecting your data.
This Article should help you understand how transaction log works an why it's growing:
http://www.sqlservercentral.com/articles/Administration/64582/