Limiting Time Machine backup size onto external drive

I have a 6TB RAID LaCie external drive that I would like to use with Time Machine. My mac has a 1TB HD which is not full. I do not want Time Machine to fill up my external drive with multiple backups. Is there some way to limit how much space Time Machine will use on an external drive? My understanding is that Time Machine will fill up the drive completely, then start overwriting the oldest files.

I do not think that I could partition the drive. But I am not sure how to do that, if it works with mac, and if I can do it now without reformating the drives. I am looking to see if there is a solution on the Time Machine software side.