TrueNAS CORE Version Documentation
This content follows the TrueNAS CORE 13.0 releases. Use the Product and Version selectors above to view content specific to different TrueNAS software or major version.
Adding Zvols
3 minute read.
A ZFS Volume (Zvol) is a dataset that represents a block device. These are needed when configuring an iSCSI Share.
To create a zvol in a pool, go to Storage > Pools then click and Add Zvol.
To quickly create a Zvol with the default options, enter a name for the Zvol, a size, and click SAVE.
See Zvols Screen for more information on zvol settings.
To set the zvol block size, click ADVANCED OPTIONS on the ADD ZVOL screen. This adds the Block Size setting near the bottom of the screen. Select that option that suits the use case or uses the information below to help determine the correct setting to use.
To see options for an existing zvol, click more_vert next to the desired zvol in Storage > Pools:
Use Delete zvol to remove the zvol from TrueNAS.
Deleting a zvol also deletes all snapshots of that zvol. Use Edit Zvol to open the zvol creation form to change the previously saved settings. Similar to datasets, a zvol name cannot be changed. Use Create Snapshot to take a single current-point-in-time image of the zvol and save it to Storage > Snapshots. A snapshot name is suggested in Name along with an extra option to make the snapshot Recursive is available.Deleting zvols can result in unrecoverable data loss! Be sure that any critical data is moved off the zvol or is otherwise obsolete.
When the selected zvol is cloned from an existing snapshot, Promote Dataset is available. When a clone is promoted, the original volume becomes a clone of the clone, making it possible to delete the volume that the clone was created from. Otherwise, a clone cannot be deleted while the original volume exists.
When the zvol is created with encryption enabled, additional Encryption Actions are displayed.