4. Fast and lightweight deletion

Efficient data deletion in a distributed storage system is often overlooked, yet it is a complex operation that can be time-consuming or may only release disk space during deferred maintenance tasks.

UltiHash avoids both drawbacks: by maintaining reference accounting information directly on the level of storage service instances, we provide a very efficient delete operation avoiding cluster-wide coordination protocols. Furthermore, as soon as a data fragments are no longer used by any object stored in the cluster, the disk space they occupied is reclaimed instantly.