hesela.devZFS clone promotion
ZFS clone promotion reverses the dependency between a clone and its origin dataset and transfers ownership of the origin snapshot and earlier snapshots to the promoted dataset.
Accounting: the former origin becomes a clone, and the promoted dataset takes ownership of the relevant snapshots and their space accounting. The operation consumes no new space, but the new accounting must fit and snapshot names must not conflict. [1]
Recovery boundary: promotion changes ownership and dependency, not the location of a recovery copy. It does not by itself provide protection against loss of the shared pool. This is a failure-boundary inference, not a measured recovery result. [2] [1]
Pending deletion: promotion does not remove every dependency on a deferred origin snapshot. The former origin becomes a clone and snapshot ownership changes; recheck the snapshot's name, holds and clones instead of treating promotion as deletion of the last clone. [1]
Relations
- related
- ZFS dataset clone, Storage snapshot, Copy-on-write (storage), ZFS deferred snapshot destruction
Citations
- OpenZFS v2.3: zfs-promote(8), origin reversal and snapshot accounting
- OpenZFS v2.3: zfsconcepts(7), dataset clones and block cloning
Sources & caveats
- Source review of OpenZFS v2.3 documentation; no pool, promotion or recovery experiment was performed.