SnapRAID and mergerfs: Pooling Mismatched Drives Without Real RAID
Most data hoarders don’t start with a matched set of drives. They start with whatever was on sale, whatever got shucked (see the hard drive shucking guide if that’s new to you), and whatever got inherited from an old build, added one or two at a time over a couple of years. The RAID redundancy guide on this site, and ZFS along with it, both assume something that mismatched-drive hoarders usually don’t have: drives that are the same size, ideally bought in a batch, treated as one block device. Buy a 4TB, then an 8TB eighteen months later, then a random 6TB that came out of a NAS somebody was tossing, and a real RAID array either wastes most of the bigger drives down to the smallest one’s capacity, or just won’t build at all. ...