Attaches and detaches ZFS filesystems from FreeBSD jails. A ZFS dataset can be attached to a jail by using the “zfs-jail jail” subcommand. You cannot attach a dataset to one jail and the children of the same dataset to another jail. You can also not attach the root file system of the jail or any dataset which needs to be mounted before the zfs rc script is run inside the jail, as it would be attached unmounted until it is mounted from the rc script inside the jail. To allow management of the dataset from within a jail, the jailed property has to be set and the jail needs access to the /dev/zfs device. The quota property cannot be changed from within a jail. See jail(8) for information on how to allow mounting ZFS datasets from within a jail.

A ZFS dataset can be detached from a jail using the “zfs-jail unjail” subcommand.

After a dataset is attached to a jail and the jailed property is set, a jailed file system cannot be mounted outside the jail, since the jail administrator might have set the mount point to an unacceptable value.