The Gemini replicated file system test-bed

The Gemini system is a replicated file system test-bed designed for local area networks and is built using ordinary host UNIX machines. Gemini was designed as a means to empirically test consistency and recovery schemes for replicated files in a distributed environment. A principle objective is to protect files against a fixed number of host and network failures while maintaining consistent data. Gemini replicated files are implemented as several copies of ordinary files that reside on distinct hosts. We present the Gemini system test-bed design and discuss three consistency and recovery schemes: voting with witnesses, dynamic voting, and semi-synchronous control. Empirical and analytic performance results are presented.