Synology uses BTRFS weirdly, on top of dmraid, which negates the most well-known BTRFS bugs in their RAID5/6 implementation*. Best I can tell they also have som

Synology uses BTRFS weirdly, on top of dmraid, which negates the most well-known BTRFS bugs in their RAID5/6 implementation*. Best I can tell they also have some custom modifications in their implementation as well, though it's hard to find much info on it. * FWIW, I used native BTRFS RAID5 for years and never had an issue but that's just anecdata