I couldn’t find that documented anywhere, so I thought it might be worth mentioning that you can move a duration Machine database from one disk to another using Disk Utility. Using the Restore feature in Disk Utility, you can “restore” the instance Machine disk to another disk and retain the history of changes. that could be useful whether you’ve outgrown your date Machine backup drive, and want to migrate your existing backups to a new, larger drive. You should turn instance Machine off

before doing starting that process, of course.

Be aware that the disks will have the same name and info, so it might confuse instance Machine. For example, after I activated duration Machine on the newly-created disk, I plugged in the old disk, and it showed up as a day Machine drive, but the backup folded. It’s probably best to avoid having both of them plugged in. At the very least, rename one of them.

Original post by (author unknown)