I have a 4 TB My Book. I would like to make two partitions, using the smaller one to do Time Machine Backups for my 256GB MacBook Pro, and using the other partition as my main repository for Photos. I want to use Backblaze to back up the photos, which they will do for a USB Hard Drive, but not if it houses Time Machine Backups. Does this sound like an ok plan, and if so, how do I get directions to partition the drive? Thanks for any help you can offer.