An Introduction To PZQ

PZQ is a persistent store daemon by Mikko Koppanen which uses the ZeroMQ messaging socket library (version 2) for communication and Kyoto Cabinet for disc and in memory data storage. Using ZeroMQ makes the service almost totally language independent - it’s accessible by anything that has ZeroMQ bindings (though we’ll use PHP in the examples, and the client library supplied along with PZQ).
Following the ZeroMQ and Unix philosophy of doing few things, but doing them well, PZQ is designed to act as a simple store-and-forward device, with the following sorts of use cases as the main objective, each of which is discussed below:

1. Provide a replacement for ZeroMQ SWAP
2. Perform as an asynchronous job queue

It's worth noting this is not the solution to every problem; this is a simple component that can be part of a good solution given certain constraints, such as the one being laid out here.

https://github.com/mkoppanen/pzq/wiki/An-Introduction-To-PZQ