How to make a raid type in one folder on linux (ubuntu server)?

Question

ubuntu

I have a bunch of all kinds of hdd, different volumes, etc., I want to make a backup server based on unnecessary but useful rubbish,
but for the backup that I chose (urbackup) you need to specify only 1 folder, you can’t connect anymore,
I heard something out of the corner of my ear that btrfs and there you can somehow, but I don’t even know how to google, tell me :)

Answer 1

when you create btrfs just list all your partitions and say you want a linear distribution

mkfs.btrfs -d single /dev/sdb /dev/sdc /dev/sdd /dev/sde

this is not even a raid, since the data is not spread over the disks, but simply sequentially fills the space (though since btrfs is a cow file system, each next write goes to a new location, so that a permanent write to the disk will periodically wander between disks, which means when reading different files will spread the load
And yes, the death of one disk will most likely create a mess of missing files
https://btrfs.wiki.kernel.org/index.php/Using_Btrf...