Kubernetes 1.36 Restores a Lost Guarantee for Database Backups
The New Stack, Tuesday, September 15th, 2026
Volume group snapshots bring back the storage-array consistency group that CSI's one-PVC-one-snapshot model discarded.
Restoring a PostgreSQL cluster whose data directory and write-ahead log live on separate PersistentVolumeClaims can fail even when every snapshot reported success, because the WAL references pages never captured in the data files.
The backup was not corrupted in transit; it was inconsistent the moment it was taken. Enterprise storage arrays solved this decades ago with consistency groups that froze a set of LUNs at the same instant, but the Container Storage Interface standardized snapshots around a single VolumeSnapshot scoped to one PVC.
Backup tools enumerate PVCs and snapshot them in sequence, so multi-volume applications lose point-in-time coherence. Most teams never notice, because the gap only surfaces at restore time after an incident, when it is far too late to act.