But ZFS also comes with an uncomfortable truth that doesn't get talked about enough: the filesystem is only as good as the operating system wrapping it. And if you're running ZFS on a generic Linux distribution, you're often signing up for more risk, maintenance, and subtle breakage than you expect. ZFS works on Linux, and many use it daily, but it's not a seamless, built-in part of the kernel. Instead, it's an add-on with caveats, and setting it up can feel frustratingly difficult. //

The problem with ZFS is Oracle
Licensing is a major issue

the Linux kernel's GPLv2 license is legally incompatible with ZFS's CDDL license, meaning that it can't be combined with the Linux kernel. Oracle's licensing is the major bottleneck.