What was wrong with LVM snapshots? Performance?
in zfs every write is 'copy on write', so snapshots have 'zero' cost, and multiple snapshots can use same data. in LVM every snapshot is standalone and has all the information it needs. also LVM doesn't have snapshot-based replication, and DRBD+ wasn't opensource/free at that time either ;-
Though reasons of OpenSolaris vs Solaris are different.
Domas