zfs-jail.8

ZFS-JAIL(8) System Manager's Manual ZFS-JAIL(8)

zfs-jail — attach or detach ZFS filesystem from FreeBSD jail

zfs jail jailid|jailname filesystem

zfs unjail jailid|jailname filesystem

The zfs-jail functionality can be used to assign a dataset onto a running FreeBSD system zfs(8) management utilities to be run inside of the jail(4).

To allow management of the dataset from within a jail, the jailed property should be set and the required devfs.conf(5) entries to expose /dev/zfs device within the jail must be present. The property cannot be changed from within a jail.

To use this functionality, the jail needs the and parameters set to and the parameter set to a value lower than .

The subcommands are as follows:

jailid|jailname filesystem
Attach the specified filesystem to the jail identified by JID jailid or name jailname. From now on this file system tree can be managed from within a jail if the jailed property has been set.

You cannot attach a jailed dataset's children 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.

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.

jailid|jailname filesystem
Detaches the specified filesystem from the jail identified by JID jailid or name jailname.

zfsprops(7), jail(8)

The root directory of jail can not be delegated to the jail with this utility because the jail must be running with a valid root directory.

Jails are a FreeBSD feature and are not relevant on other platforms. See jail(8) for more information on managing jails, or zfs-zone(8) for the equivelant functionality on Linux.

November 4, 2025 Debian