CowboyRobot writes: At ACM's Queue magazine, Wyatt Lloyd of Facebook writes that "Systems that sacrifice strong consistency gain much in return. They can be always available, guarantee responses with low latency, and provide partition tolerance. We coined the term ALPS for systems that provide these three properties—always available, low latency, and partition tolerance—and one more: scalability. Scalability implies that adding storage servers to each data center produces a proportional increase in storage capacity and throughput. Scalability is critical for modern systems because data has grown far too large to be stored or served by a single machine. The question remains as to what consistency properties ALPS systems can provide. Before answering this, let's consider the consistency offered by existing ALPS systems. For systems such as Amazon's Dynamo, LinkedIn's Project Voldemort, and Facebook/Apache's Cassandra, the answer is eventual consistency."