[[storage_zfspool]]
Local ZFS Pool Backend
----------------------
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:pve-toplevel:
:title: Storage: ZFS
endif::wiki[]

Storage pool type: `zfspool`

This backend allows you to access local ZFS pools (or ZFS file systems
inside such pools).


Configuration
~~~~~~~~~~~~~

The backend supports the common storage properties `content`, `nodes`,
`disable`, and the following ZFS specific properties:

pool::

Select the ZFS pool/filesystem. All allocations are done within that
pool.

blocksize::

Set ZFS blocksize parameter.

sparse::

Use ZFS thin-provisioning. A sparse volume is a volume whose
reservation is not equal to the volume size.

mountpoint::

The mount point of the ZFS pool/filesystem. Changing this does not
affect the `mountpoint` property of the dataset seen by `zfs`.
Defaults to `/<pool>`.

.Configuration Example (`/etc/pve/storage.cfg`)
----
zfspool: vmdata
        pool tank/vmdata
        content rootdir,images
        sparse
----


File naming conventions
~~~~~~~~~~~~~~~~~~~~~~~

The backend uses the following naming scheme for VM images:

 vm-<VMID>-<NAME>      // normal VM images
 base-<VMID>-<NAME>    // template VM image (read-only)
 subvol-<VMID>-<NAME>  // subvolumes (ZFS filesystem for containers)
 
`<VMID>`::

This specifies the owner VM.

`<NAME>`::

This can be an arbitrary name (`ascii`) without white space. The
backend uses `disk[N]` as default, where `[N]` is replaced by an
integer to make the name unique.


Storage Features
~~~~~~~~~~~~~~~~

ZFS is probably the most advanced storage type regarding snapshot and
cloning. The backend uses ZFS datasets for both VM images (format
`raw`) and container data (format `subvol`). ZFS properties are
inherited from the parent dataset, so you can simply set defaults
on the parent dataset.

.Storage features for backend `zfs`
[width="100%",cols="m,m,3*d",options="header"]
|==============================================================================
|Content types  |Image formats  |Shared |Snapshots |Clones
|images rootdir |raw subvol     |no     |yes       |yes
|==============================================================================

Encryption
~~~~~~~~~~

ZFS supports encryption of dataset hierarchies. Each encrypted dataset, is
either an `encryption_root`, storing the properties for encryption itself or
descendant of its `encryption_root` - see the `zfs-load-key(8)` manpage for
details.

Sending and receiving encrypted datasets is subject to constraints as some
encryption parameters (initialization vectors for the symmetric ciphers) need
to be either transferred with the data, breaking inheriting the encryption
properties on the receiving side, or need to be recreated on target, requiring
the data to be sent unencrypted - see the `zfs-recv(8)` manpage for details.

For migration and storage replication of encrypted datasets in {pve}, the
data is sent without the encryption properties, and the state of encryption
is determined by the target.

If you want to send and receive encrypted ZFS datasets, you need to ensure that
all involved storages on all nodes are encrypted.

Examples
~~~~~~~~

It is recommended to create an extra ZFS file system to store your VM images:

 # zfs create tank/vmdata

To enable compression on that newly allocated file system:

 # zfs set compression=on tank/vmdata

You can get a list of available ZFS filesystems with:

 # pvesm scan zfs

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See Also
~~~~~~~~

* link:/wiki/Storage[Storage]

* link:/wiki/ZFS_on_Linux[ZFS on Linux]

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