---
name: "zfs-jail"
section: "8"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/zfs-jail"
---

# zfs-jail(8)

attach or detach ZFS filesystem from FreeBSD jail

## NAME

**zfs-jail** – attach or detach ZFS filesystem from FreeBSD jail

## SYNOPSIS

**zfs** **jail** *jailid*\|*jailname* *filesystem*

**zfs** **unjail** *jailid*\|*jailname* *filesystem*

## DESCRIPTION

The **zfs-jail** functionality can be used to assign a dataset onto a running FreeBSD system jail(4), allowing [zfs(8)](/zfs/8.md) 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)](/devfs.conf/5.md) entries to expose */dev/zfs* device within the jail must be present. The **quota** property cannot be changed from within a jail.

To use this functionality, the jail needs the **allow.mount** and **allow.mount.zfs** parameters set to **1** and the **enforce\_statfs** parameter set to a value lower than **2**.

The subcommands are as follows:

-

  **jail** *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.

-

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

## SEE ALSO

[devfs.conf(5)](/devfs.conf/5.md), [zfsprops(7)](/zfsprops/7.md), [jail(8)](/jail/8.md)

## CAVEATS

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)](/jail/8.md) for more information on managing jails, or [zfs-zone(8)](/zfs-zone/8.md) for the equivalent functionality on Linux.