ZBOSS by ZETTALANE Systems isn't to be confused with the other ZBOSS, the ZigBee Open Source Stack. ZBOSS isn't also to be confused with Red Hat's JBoss. I was just contacted by ZETTALANE on Friday about the 6.5 release as their apparent Red Hat Enterprise Linux based distribution that ships with ZFS for "unified Software Defined Storage with iSCSI, FC and NAS connectivity. For enterprise-class features it packs unlimited snapshots, data replication and High Availability in active-active mode." ZBOSS is short for the ZettaByte OpenStorage Server.
ZBOSS Linux Server isn't free to use, only just under a 30 day evaluation license. Unfortunately the company didn't provide much more information on their ZFS-focused enterprise Linux distribution but a few more bits of information can be found via Zettalane.com. Most likely they are using the out-of-tree ZFSOnLinux work for a ZFS file-system module that works natively with the Linux kernel rather than the FUSE-based alternatives, with their being no mainline ZFS Linux support due to the ZFS' CDDL license not being compatible with the GPLv2.