ClickHouse Coordinates a Cluster-Wide Backup with ZooKeeper
A cluster-wide backup is a ZooKeeper-coordinated election: one owner per data file, a stage barrier between phases, and a consensus loop over metadata.
Backups
ClickHouse Incremental Backups Store Only the Changed Tail of a File
Incremental backups reuse the base backup’s bytes: only the suffix after a verified shared prefix is uploaded, and the restore concatenates the two halves.