Geo-Replicated Buckets : An Optrimistic Geo-Replicated Shim for Key-Value Store

Abstract: This work introduces GeoD and VersionD. GeoD is a causally-consistent georeplication shim for key-value stores. GeoD enables the separation of concerns regarding replication and convergence from key-value stores, while preserving all of their read-only functionality. VersionD extends the feature set of GeoD by providing a versioning API, allowing applications to store multiple values for a given object, and to use context-specific conflict-resolution rules. We also discuss an efficient architecture for optimistically replicated systems, where all the storage replicas persist data in a common shared DHT. Since most key-value stores don’t support versioning and GeoD relies on versioning support from the key-value store, we developed a shim layer that also augments the traditional core API with extra versioning operations and logic.