Many distributed storage systems achieve high data access through- put via partitioning and replication, each system with its own ad- vantages and tradeoffs. In order to achieve high scalability, how- ever, today’s systems generally reduce transactional support, disal- lowing single transactions fromspanning multiple partitions. Calvin is a practical transaction scheduling and data replication layer that uses a deterministic ordering guarantee to significantly reduce the normally prohibitive contention costs associated with distributed transactions. Unlike previous deterministic database system proto- types, Calvin supports disk-based storage, scales near-linearly on aclusterofcommoditymachines,andhasnosinglepointoffail- ure. By replicating transaction inputs rather than effects, Calvin is also able to support multiple consistency levels—including Paxos- based strong consistency across geographically distant replicas—at no cost.