Oracle Solaris ZFS Administration Guide

ZFS Quotas and Reservations for File System Data Only

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.

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.