It didn't take long for some overly zealous Linux troll to start spreading the FUD about ZFS. This fool sent an email to the firstname.lastname@example.org mailing list entitled "Ten Reasons To *NOT* Use ZFS".
I haven't read this much FUD in a long time, and I'm not the only one who agrees. Razvan Corneliu Vilt gave a great response, and he doesn't even use Solaris/OpenSolaris.
It is blatantly clear from this email that this guy has some big issues with Sun and was using any excuse to add to his list of issues, without thinking about them in context. For example, WTF does Java and 64 bit Mozilla plugins have to do with ZFS? ZFS is written entirely in C, not Java.
It's also clear this guy hasn't actually thought about ZFS (it's features, it's possibilies, it's ease of use) and dismissed it right from the start because it didn't fit in with the way Linux does things.
Wake up and smell the coffee dude - Linux isn't the only open source operating system, and the GPL isn't the only open source license. Oh and try working on your lovely RedHat/Fedora system without any of the code Sun contributed to the likes of Xorg, Gnome, Evolution etc before you start bitching about the Sun's contributions to FOSS. I pretty much guarentee you won't have much fun.