TrueNAS CORETrueNAS CORE Nightly Development Documentation
This content follows experimental early release software. Use the Product and Version selectors above to view content specific to a stable software release.

Zvols Screen

Use the Storage > Pools Add Zvol screen to add a zvol to a pool.


Basic Options

Zvol nameEnter a short name for the zvol. Using a zvol name longer than 63-characters can prevent accessing zvols as devices. For example, a zvol with a 70-character filename or path cannot be used as an iSCSI extent. This setting is required.
CommentsEnter any notes about this zvol.
Size for this zvolSpecify size and value. Units like t, TiB, and G can be used. The size of the zvol can be increased later, but cannot be reduced. If the size is more than 80% of the available capacity, the creation fails with an out of space error unless Force size is also selected.
Force sizeSelect to force the system to create a zvol that brings a pool to over 80% capacity (not recommended). By default, the system does not create a zvol if that operation brings the pool to over 80% capacity.
SyncSelect an option from the dropdown list that sets the data write synchronization. Inherit sets zvol to get sync settings from the parent dataset, Standard uses the sync settings requested by the client software, Always that waits for data writes to complete,or Disabled that never waits for writes to complete.
Compression levelSelect a compression option from the dropdown list. Select Off to not compress data to save space. Refer to Compression for a description of the available algorithms.
ZFS DeduplicationDo not change this setting unless instructed to do so by your iXsystems support engineer.
SparseSelect to provide thin provisioning. Use with caution as writes fail when the pool is low on space.
Read-onlySelect an option from the dropdown list to set whether the zvol can be modified. Options are Inherit to get and use the parent pool or root dataset settings, On to prevent modifying the zvol, or Off to allow the zvol to be modified.
Inherit (Encryption Options)Select to enable the zvol to use the encryption properties of the root dataset.

Selecting ADVANCED OPTIONS adds one additional setting.

Block sizeselect the default Inherit or select from the other dropdown list options 4KiB, 8KiB, 16KiB, 32KiB, 64KiB or 128KiB. See Creating a Zvol for more information on these options and block sizes.

SUBMIT activates after all required fields are populated. Use to save settings.

Use CANCEL to exit without saving settings and display the Pools screen.