I have an 2 TB external hard drive. It is formatted as NTFS format, supported by ntfs-3g which is installed using Homebrew. There is already about 500 GB data existing on it that I need to keep. I now want to use the rest of the space on it to store my TimeMachine backups. There is only one partition on the hard drive. I do not have other hard drives to shuffle the data. How can I start to use this hard drive to store my Time Machine backups?