Thanks for information.

I use COPY_ONLY backups if I need to take an ad-hoc copy of a production database for urgent debugging in a development environment without interrupting the current backup sequence for the database.

All of my current production databases employ weekly full backups, daily differential and half hourly transaction log backups so if I perform a random full backup without specifiying COPY_ONLY all of the files the server team have been copying off onto tape for me become out of date very quickly!

If you like me have written any custom disaster recovery type backup/restore scripting then you might have discovered that there is a new column (2005 onwards) in the msdb.dbo.backupset table called [font="Courier New"]is_copy_only[/font]. This is set to a 1 when a backup is taken with the COPY_ONLY switch.