Solaris 10 10/08 Release : In addition to the existing ZFS quota and reservation features, this release includes dataset quotas and reservations that do not include descendents, such as snapshots and clones, in the disk space accounting.
The refquota property enforces a hard limit on the amount of disk space that a dataset can consume. This hard limit does not include disk space used by descendents, such as snapshots and clones.
The refreservation property sets the minimum amount of disk space that is guaranteed for a dataset, not including its descendents.
For example, you can set a 10-GB refquota limit for studentA that sets a 10-GB hard limit of referenced disk space. For additional flexibility, you can set a 20-GB quota that enables you to manage studentA's snapshots.
# zfs set refquota=10g tank/studentA # zfs set quota=20g tank/studentA
For more information, see Setting ZFS Quotas and Reservations.