A snapshot is a read-only point-in-time copy of a file system. The copy-on-write design

of ZFS makes them essentially “free” - They are space efficient and instantaneous, providing an invaluable part of backup strategies and synchronizing data between systems.

Incorrect:

Incorrect:

NotA:A ZFS vdev (aka "virtual device") is either:

a single disk, or

two or more disks that are mirrored, or

a group of disks that are organized using RAID-Z.

There are also special kinds of vdevs like hot-spares, ZIL or cache devices, etc.

Not D:

Clones are writeable snapshots, ideal for storing many private

copies of shared data for operations such as data migration, test

and development, or backup.