Backing up Libraries

Hello, just making sure i'm backing up my library correctly onto another drive. i have one entire library connected to an external drive, I consolidated + copied everything to the second drive. let's say I want to continue working off the first one, add additional media, and sync up with the second drive. Do I just make a new event and consolidate that individually? Normally I would use finder to sync the backups, but it seems fcp gets cranky with "error" permissions messages when I do that.

Use backup software like Carbon Copy Pro that will recognize OS X "packages" and update package contents as needed. Then you're not overwriting the entire Library all the time.

Or, store all footage in an exterior location from the library, then you can backup your media folder and library individually, and manually.