4. Other Approaches
Non-transactional replication using timestamped updates and variations of Thomas’ write rule
- directory services are managed this way
Quorum consensus per-transaction
- Read and write a quorum of copies
- Each data item has a version number and timestamp
- Each read chooses a replica with largest version number
- Each write increments version number one greater than any one it has seen
- No special work needed during a failure or recovery