vdev
also: virtual device
A virtual device in ZFS—a logical representation of physical storage (disk, partition, or file) that ZFS uses to manage data redundancy and allocation.
A vdev (virtual device) is ZFS's abstraction layer between physical storage hardware and the storage pool. It represents one or more physical devices (like /dev/sda, /dev/sdb) organized in a specific configuration such as a single disk, a mirror, a RAID-Z stripe, or a spare.
Multiple vdevs are combined into a zpool (storage pool), which manages data distribution across them. For example, a zpool might contain two mirror vdevs, each mirroring two disks, providing redundancy at the vdev level.
Common vdev types include: single disk, mirror (RAID-1), raidz/raidz2/raidz3 (RAID-Z variants with parity), spare (hot-spare device), and cache/log (special-purpose vdevs for performance). You can view vdev configurations with zpool status.