Oracle and storage IOs, explanations and experience at CERN

The Oracle database system is used extensively in the High Energy Physics community. Critical to the efficient running of these databases is the storage subsystem, and over the years Oracle has introduced new ways to access and manage this storage, e.g. ASM (10.1), Direct NFS (11.1), and Exadata (11.1). This paper presents our experience over the past few years with the different storage access and management features, and gives a comparison of each functionality. Also compared are the different solutions used at CERN, and the Tier 1 sites for storing Oracle databases.