Date: 23-09-10 07:16
About the free space
zpool list shows you the size of all your disks lets say (5 * 250 GB=~1.2 TB) including parity space.
zfs list shows you the space available to filesystems/volumes, after all the parity is accounted for. With 2 parity disks, you get 3 * 250 GB = ~750 GB. Add in ZFS overhead for redundant metadata and other info, and you get what you see.
Post Edited (23-09-10 13:54)