I'm not sure it's fair to summarize the Linux community's complaint about ZFS as the latter being "written for kernels that don't really have a VFS layer." Sola

I'm not sure it's fair to summarize the Linux community's complaint about ZFS as the latter being "written for kernels that don't really have a VFS layer." Solaris very much has a VFS layer, and ZFS plays with it. What's different about ZFS is that, from most storage stacks' perspectives, it is also a volume manager. Linux people claim this is a layering violation; ZFS' architects claim that integrating traditional functions of filesystems and volume managers let them innovate, e.g., by closing the RAID write hole.