Does FreeBSD 9.2 support the new ZFS pool version 5000? It's hard to imagine that it wouldn't, but the release announcement at http://www.freebsd.org/releases/9.2R/announce.html and http://www.freebsd.org/releases/9.2R/relnotes.html do not mention this.
However, FreeBSD 8.4 makes a specific statement about v5000 at http://www.freebsd.org/releases/8.4R/announce.html
However, FreeBSD 8.4 makes a specific statement about v5000 at http://www.freebsd.org/releases/8.4R/announce.html
The FreeBSD Release Engineering Team is pleased to announce the availability of FreeBSD 8.4-RELEASE. This is the fifth release from the 8-STABLE branch which improves on the functionality of FreeBSD 8.3 and introduces some new features. Some of the highlights:
* Feature flags 5000 version of the ZFS filesystem.