quick snapshot tour

To take a snapshot of zfs pool pool/aqua you have to run an example command:
# zfs snapshot pool/aqua@cold
where the cold is the name of a newly created shot.

You could find it in (pool/aqua/) .zfs/snapshot directory. By default it's hidden.
You can change this behaviour by setting snapdir variable on pool/aqua to visible:
# zfs set snapdir=visible pool/aqua

To take advantage of snapshots in another way, use it to quickly reproduce the filesystems with clone method.
The clone is functional fs instead of snapshot which cannot be modified (ro mode).
# zfs clone pool/aqua@cold pool/ice

It's a good habit to name the snapshop in a way enabling you to remember the creation time.
In a case of memory leak do the following:
# zfs get creation pool/aqua@cold

To destroy snapshot simply run:
# zfs destroy pool/aqua@cold