High availability solutions for transactional database systems

In our increasingly wired world, there is a stringent need for the IT community to provide uninterrupted services of networks, servers and databases. Considerable efforts, both by the industrial and academic community have been directed to this end. In this paper, we examine the requirements for high availability, measures used to express it, and approaches used to implement this for databases. We present a high availability solution, using off the shelf hardware and software components, for transactions based applications and give our experience with this system.