Sparing for availability and sparing for confidence – use for cloud computing services

Cloud computing services, Web hosting companies and Data Centers guarantee high service availability to the users (up to 99.999%). While industry standards exist for tier I – IV data centers, following the standard does not guarantee the required availability. Therefore, reliability and maintenance optimizations are crucial. Standard spare optimization strategies include sparing for confidence (where the goal is to minimize the probability of a stock-out), and cost optimization (where spare and down-time costs are minimized). However, in the case of cloud services a different approach is needed: sparing for availability.