Time machine will keep copies of files that it has backed up, even when you delete them from the source disk. Seems like it may be a better/more reliable option than Time Machine for me, even with the $40 price-tag I think I may look into CCC, I am watching a few videos on it now. Then you would have no copies of those 500 photos. Once that Time Machine backup drive starts to fill, Time Machine might silently start deleting some or all of those 500 photos to make room for new (and as far as it can tell, more critical backups). As long as there is space on the Time Machine backup drive to store newer backups, it might keep the 500 photos. I would not count on Time Machine keeping 500 deleted files around forever, out of the goodness of its heart.
#Best external hard drives for macbook air archive
What you seem to be talking about doing is deleting files from the internal (source) drive, and using the Time Machine backup disk as an archive disk: a disk that would contain the one and only copies (or sets of copies) of each of the 500 deleted photos. If you were using it as a backup for files you had not deleted, you'd have two copies of the latest version of each photo: one on the internal drive, one on the Time Machine backup drive. Yes, I gathered that you were doing something riskier than using Time Machine as a backup for your current files. Maybe there is something better though like you both mentioned, some cloning tool. I could just as easily bypass Time Machine and drag and drop directories to my external HD, but figured Time Machine may be a more efficient way to do it. My question was more around would the 500 on my external drive be deleted given the scenario laid out. I think you can set it up to manually execute or automatically execute, when a external drive is present. I wasn't intending on solely using Time Machine as my backup, I was simply going to use it to facilitate a backup to an external hard drive. I would archive photos to external drives using a clone-type backup tool (or even a Finder copy). So if you want to keep all 1,000 photos, I would NOT delete 500 of them from the internal drive and assume that Time Machine will preserve the other 500 forever for you. Also, if you start running out of space for backups of current files, it may decide that some of the backups of old files are expendable.
You can't count on it recording every older version of a file in the first place. Time Machine is not a version control system, like ClearCase, cvs, or git.