That allows ZoL to run on many different * nixes, which means that if Linux made a drastically breaking change, you could use it on another OS, sure. And the L

That allows ZoL to run on many different * nixes, which means that if Linux made a drastically breaking change, you could use it on another OS, sure. And the Linux kernel has made numerous breaking changes to their APIs that ZoL has been able to work around. So it has happened, they've just been able to deal with it. Despite the belief that a breaking change that ZoL can't work around being improbable, it is still possible. The Linux Kernel could majorly overhaul an API in a major version release, in a way that ZoL can't handle. Given ZoL's status as a separate kernel module not under a GPL license, it's entirely possible that no amount of yelling gets the Linux maintainers to change their mind. In fact Wowfunhappy notes a discussion along those lines is happening currently based on function symbols being removed for an API required for Mac hardware support. And sure, that compatibility layer means that users could switch to FreeBSD, or Solaris, etc, and keep using ZFS. If that happens, does Delphix change their target platform again to move to FreeBSD? Or do they come up with another solution, and stop supporting ZoL?