In: LNCS 2187: Computer Safety, Reliability and Security, pages 238-pp. 20th International Conference, SAFECOMP 2001, Budapest, Hungary, September 26-28, 2001, Proceedings / U. Voges (Ed.) --- Springer Verlag, 2001.
Abstract: To ensure the consistency of database subsystems involved in communication systems (e.g., telephone systems), appropriate scheduled maintenance policies are necessary. Audit operations, consisting in periodic checks and recovery actions, are typically employed in databases to cope with run time faults which may affect the dependability and quality of service of the overall system. This paper aims at investigating on appropriate tuning of audit operations, so as to find optimal balances between contrasting requirements, namely satisfactory database availability and low overhead due to audits. For this purpose, a methodology to analyse the behaviour of the database under scheduled maintenance is here suggested. Analytical models, essentially based on Deterministic and Stochastic Petri Nets (DSPN), are defined and analysed, in terms of dependability indicators. A sensitivity analysis wrt to the most affecting internal and external parameters is also performed on a case study.