As we all know, ZFS is by far the best file system.
People have workarounds and solutions which are kind of 2nd tone replacements to work on Linux, but either ways, all these solutions are not really good replacements as they either are not stable enough or lack some of the salient features of ZFS.
KQ has ported ZFS to Linux and was a much awaited release since January 2010.
We are releasing the closed beta in last week of August/first week of september and are looking for closed beta customers who can test it for free on some environments.
Mail me at email@example.com to register.
Feel free to put forward any questions as well.