Giraph utilizes Apache Hadoop's MapReduce implementation to process graphs.
Facebook used Giraph with some performance improvements to analyze one trillion edges using 200 machines in 4 minutes.
[1] Giraph is based on a paper published by Google about its own graph processing system called Pregel.
[2] It can be compared to other Big Graph processing libraries such as Cassovary.
[3] As of September 2023, it is no longer actively developed.