ZFS presents a pooled storage model that completely eliminates the concept of volumes and the associated problems of partitions, provisioning, wasted bandwidth and stranded storage. Thousands of filesystems can draw from a common storage pool, each one consuming only as much space as it actually needs. The combined I/O bandwidth of all devices in the pool is available to all filesystems at all times.
...
t's likely that administrators will be creating a file system for every single user and probably a file system for every project as well. ZFS provides a powerful hierarchical naming scheme for managing this, potentially very large, name space.
Full story:
http://arstechnica.com/news.ars/post/20051117-5595.html
Sorce:
arstechnica.com