Before considering backups you’re going to have to answer a few questions which important to you
- Do you need encrypted backups? Do you need the transfer encrypted between Ubuntu and FreeNAS?
- Do you need versioned backups?
- How big do expect the backups to be after the initial backup?
- Are you looking at a file system backup solution, or more of a block device type solution
- Is a GUI important to you or can you work from the command line and have the backups automated through something like cron?
- Are you looking for potentially in the future a cross platform solution or would it be simply Ubuntu/Freenas?
- Is your Ubuntu install on bare metal or a VM?
- Are you looking for a free solution or would you be open to software that you have to pay for?
- Is open source software important to you?
There are probably other considerations I haven’t thought about at present. There really isn’t unfortunately a perfect solution in every case. Your probably going to need to match your needs to the best available choices.
Whatever the method you choose, your going to have to practice, practice and practice to ensure your possible solution is robust. It’s one thing to make backups, but its another to have to restore your backups. By practice I mean you’ll need to become efficient with the restore option. That means creating a bunch of datasets, transferring or backing them up, deleting the original and then attempting a restore.
Time Machine is a versioned file system backup solution. If I loose a couple of files its really easy to go back and restore the files. Time Machine falls short however if the entire OS were to die. I would need to reinstall MacOS and then hope I could access the Time Machine shares to restore the individual files. I’ve never tested the ability to restore Time Machine data after a full OS reinstallation but something tells me there could be potential problems.