Topics

CAP Theorem

The CAP Theorem states that it is impossible for a distributed database to simultaneously guarantee more than two of the following: Consistency, Availability, or Partition Tolerance. The widely accepted theorem is often used to analyze and position new databases.

• Consistency - Every read receives the most recent write or an error.

• Availability - Every request receives a (non-error) response, without the guarantee that it contains the most recent write.

• Partition Tolerance - The system continues to operate despite an arbitrary number of messages being dropped (or delayed) by the network between nodes.

Scalability

Horizontal Scaling	Vertical Scaling
Load Balancing Required	N/A
Resilient	Single Point of Failure
Network Calls (RPC) - Slow	Inter process Communication - Fast
Data Inconsistency	Data Consistent
Scales well as users increases	Hardware Limit
Increase Hardware	Increase Capacity