"Due to potential legal incompatibilities between the CDDL and GPL, despite both being OSI-approved free software licenses which comply with DFSG, ZFS development is not supported by the Linux kernel"
@mcc btrfs
my headmate, who is obsessive over data integrity, runs btrfs on her NAS with zero issues. it has nice things like snapshotting and such. the reputation btrfs has dates back to many years ago and i don't think the issues people distrust it for have mattered for quite a while