Asymmetric Active-Active High Availability for High-end

Linux clusters have become very popular for scientific computing at research institutions world-wide, because they can be easily deployed at a fairly low cost. However, the most pressing issues of today`s cluster solutions are availability and serviceability. The conventional Beowulf cluster architecture has a single head node connected to a group of compute nodes. This head node is a typical single point of failure and control, which severely limits availability and serviceability by e#ectively cutting o# healthy compute nodes from the outside world upon overload or failure. In this paper, we describe a paradigm that addresses this issue using asymmetric active-active high availability. Our framework comprises of n + 1 head nodes, where n head nodes are active in the sense that they provide services to simultaneously incoming user requests. One standby server monitors all active servers and performs a fail-over in case of a detected outage. We present a prototype implementation based on a 2 + 1 solution and discuss initial results