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Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).

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What's an elegant way of automatically backing up the contents of a large drive to multiple smaller drives that add up to the capacity of the large drive? (lemmy.ml)

submitted 11 months ago by [email protected] to c/[email protected]

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So I have a nearly full 4 TB hard drive in my server that I want to make an offline backup of. However, the only spare hard drives I have are a few 500 GB and 1 TB ones, so the entire contents will not fit all at once, but I do have enough total space for it. I also only have one USB hard drive dock so I can only plug in one hard drive at a time, and in any case I don't want to do any sort of RAID 0 or striping because the hard drives are old and I don't want a single one of them failing to make the entire backup unrecoverable.

I could just play digital Tetris and just manually copy over individual directories to each smaller drive until they fill up while mentally keeping track of which directories still need to be copied when I change drives, but I'm hoping for a more automatic and less error prone way. Ideally, I'd want something that can automatically begin copying the entire contents of a given drive or directory to a drive that isn't big enough to fit everything, automatically round down to the last file that will fit in its entirety (I don't want to split files between drives), and then wait for me to unplug the first drive and plug in another drive and specify a new mount point before continuing to copy the remaining files, using as many drives as necessary to copy everything.

Does anyone know of something that can accomplish all of this on a Linux system?

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[–] [email protected] 4 points 11 months ago

It's going to take a little work here, but I have a large drive on my plex, and a couple of smaller drives that I back everything up to. On the large drive get a list of the main folders. You can do a "du -h --max-depth=1 | sort -hk1" on the root folder to get an idea of how you should split them up. Once you have an idea, make two files, each with their own list of folders (eg: folders1.out and folders2.out) that you want to go to each separate drive. If you have both of the smaller drives mounted, just execute the rsync commands, otherwise, just do each rsync command with the corresponding drive mounted. Here's an example of my rsync commands. Keep in mind I am going from an ext4 filesystem to a couple of ntfs drives, which is why I use the size only. Make sure and do a dry run or two, and you may or may not want the '--delete' command in there. Since I don't want to keep files I have deleted from my plex, I have it delete them on the target drive also.

sudo rsync -rhi --delete --size-only --progress --stats --files-from=/home/plex/src/folders1.out /media/plex/maindrive /media/plex/4tbbackup

sudo rsync -rhi --delete --size-only --progress --stats --files-from=/home/plex/src/folders2.out /media/plex/maindrive /media/plex/other4tbdrive