How do I migrate external drive without wiping Time machine?

[yalag]

I bought a new external drive that is a bigger for all my media files. I back them up via time machine. I don't want time machine to treat this new drive as new files because that'll waste all the space in the time machine drive. How do I tell time machine to treat content in this new drive the same as the old one?

 

[ColdCase]

I think you use disk utility to partition the new drive into two drives, one sized for what you want to allocate to TM, the other for the rest of your files. That will limit the amount of disk space TM can take to the partition size.

TM files will eventually grow to take up as much disk space as it can..