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Some reliability issues in very large databases

Very large databases are subject to unique reliability problems. The size of these databases and the statistics of device failures necessitate specialized techniques for the management of hardware problems. The article discusses the use of controlled partial redundancy to improve database reliability. Issues in the design of operating system/DBMS interfaces to facilitate high reliability are also considered. We discuss control of continued execution of queries and updates in a degraded environment, and propose ways for a query optimizer/access planner to account for hardware failures or system overload. The article concludes with a discussion of the interaction between developments in disk technology and the viability of very large databases. © 1988 John Wiley & Sons, Inc.