Since Mac OS X 10.7 (Lion) TimeMachine performs local backups to
/.MobileBackups if enabled (
tmutil enableLocal, default enabled on portable macs).
The different types of backups are color encoded in the fancy TimeMachine space thingy, local backups are white, external storage purple. They mostly differ only by a minute. What exactly is the concept of those local backups?
Are they simple a completely parallel, additional backup? Or are they at least merged into your external storage backup when you come home after begin away from your backup drive for a week? And what happens if i require lots of disk space suddenly? Do i need to remove the local backups manually?