A zvol is roughly analogous to a dataset, except it does not actually have a filesystem in it.

• It is just a block device.
• Zvols do not have the recordsize property which datasets have.
  • Instead, they have volblocksize, which is roughly equivalent.

You could, for example, create a zvol named mypool/myzvol, then format it with the ext4 filesystem, then mount that filesystem—you now have an ext4 filesystem, but backed with all of the safety features of ZFS!

• This might sound silly on a single computer—but it makes a lot more sense as the back end for an iSCSI export.