The other day I replaced a 500GB hard disk in my Mac Pro with a larger 2TB model.
I planned to use the old and proven approach of attaching the new disk, copying all the files from the old to the new and removing the new.
But then it dawned on me, that Time Machine would not recognize the swap and would backup all the data on the new disk again! Effectively doubling that set of data in my Time Machine volume.
To replace the disk the correct way you should:
1. write down the volume name of the current disk (Movies in my case), and the drive bay it is in (in case of multiple drives).
2. verify that it was under Time Machine control by opening the Time Machine preferences and checking it’s not in the list of excluded folders. Check under the options button.
3. possibly verify your time machine data is there, by selecting the volume you want to replace, and then start Time Machine from the dock.
4. shut down your system to replace the drive, in case of internal drives.
5. replace the drive with the new / larger drive
6. start the system if you shut it down in step 4.
7. start disk utility, partition the disk and give it the same name as the old volume
8. start Time Machine from the dock and select the new empty volume in the Finder
9. move back in time to the moment the data is there, select all the data, and restore it (task drop down box).
Time Machine will ask you where you want to restore the data (probably because the disk id has changed;).
10. Select the new empty volume to restore to.
Now sit back and watch Time Machine restore all data. It will take some time, but the next time Time Machine runs, and nothing has been added to the volume, it won’t backup anything since nothing has changed.