hesela.devZFS virtual device (vdev)
A ZFS virtual device (vdev) is a node in a pool's storage hierarchy representing a backing device or a supported device arrangement such as a mirror or RAIDZ group.
A leaf vdev is a backing endpoint; a top-level vdev sits directly below the pool's root. Normal pool allocations span top-level data vdevs, while mirror or parity redundancy operates within each group. Losing a required data-bearing top-level vdev beyond its redundancy can make the pool unavailable and cause data loss. [1]
A leaf can be a disk, partition or experimental file backing. An unused spare is replacement capacity, not extra current replicas. Cache devices hold read-cache copies; log devices hold separate intent-log blocks. The special and dedup classes hold authoritative allocated blocks, not disposable caches. Roles and redundancy must be checked separately; an individual member failure is not automatically whole-pool loss. [2]
Relations
- related
- ZFS, RAIDZ, ZFS separate log, Mirroring (storage), Failure domain, Resilver
Citations
- OpenZFS: VDEVs, pool hierarchy and redundancy boundaries
- OpenZFS 2.3: zpoolconcepts(7), device roles and failure states
Sources & caveats
- Pool hierarchy uses the OpenZFS Basic Concepts terminology: root, top-level and leaf.
- Failure statements concern required data-bearing vdevs, not every cache, spare or log event; no availability probability is claimed.