- Consistency - Every read receives the most recent write or an error
- Availability - Every request receives a response, without guarantee that it contains the most recent version of the information
- Partition Tolerance - The system continues to operate despite arbitrary partitioning due to network failures
Networks aren’t reliable, so you’ll need to support partition tolerance. You’ll need to make a software tradeoff between consistency and availability.
CP - consistency and partition tolerance
- Waiting for a response from the partitioned node might result in a timeout error. CP is a good choice if your business needs require atomic reads and writes.
AP - availability and partition tolerance
- Responses return the most recent version of the data available on the a node, which might not be the latest. Writes might take some time to propagate when the partition is resolved.
- AP is a good choice if the business needs allow for eventual consistency or when the system needs to continue working despite external errors.